Transcript of True Crime Vault: Do No Harm

Step into the 2020 True Crime Vault where each story is unforgettable.

How big was flying in the life of Robert Berenbaum?

South 2, climb maintain flight level 230.

Flying was his passion.

He loved to fly.

The airplane was a key part of his life.

One of the first dates he took Gail on was a flight around Manhattan in the evening on the skylight. So romantic. Please be true. Bob fits the tall, dark, and handsome. This perfect Renaissance man spoke several languages.

The first date, he said, do you want to get high tonight? We flew around the lights of Las Vegas. It was sparkling.

Pilot, surgeon, brilliant guy.

The gourmet chef. An expert skier.

Top of his class. A big catch, right, for any young lady.

Yeah, well, you can look so good on paper and have a whole other side that you can just erase it all in a heartbeat.

Flying, it's the crux of the story. It's the method that he tries to cover up his crime.

Her disappearance made headlines in New York in 1985. I get a phone call.

Turn on the TV. They've arrested Robert Birenbaum. I started screaming.

So shocked, I dropped to my knees.

You must have been blown away.

I was shocked.

Gail Birenbaum vanished from the apartment she shared with her husband Robert, a Manhattan plastic surgeon.

Bob tells police that they had an argument and she came here to the park?

Yes.

Never in a million years you'd think you'd be using cold, calculated murder in the same description as Dr. Birenbaum. I did— there's just no way.

No body.

No forensics, no eyewitness The investigative theory was that he wrapped the body up, drove it to his plane in New Jersey, flew the plane out over the ocean. You know, they've charged that you took her on an airplane... He has no comment. ...and threw her out.

Disbelief switched to, good God, this guy was a psychopath.

My God, you gotta think it's a movie.

Crime and Punishment. That's the story.

Dr. Birnbaum. That's stuff you see on TV. That's not real. Right?

The Birnbaum story, when you get right down to it, is Dr. Jekyll and Mr. Hyde.

As physicians, we all take an oath that oath to above all do no harm. I love you.

In the 1980s, New York City was a very different place. It was a grittier place. It was a dirtier place. There was graffiti everywhere, covering all parts of every subway car.

The homicide rate in the '80s was astronomical. I mean, there was thousands. There were a lot of drug gangs. It was a very violent time in New York, the '80s.

Throughout the city, there were bubbles of safety. On the Upper East Side, that was one of them. The Upper East Side was the place where you wanted to live.

The Upper East Side was the music to the beginning of The Jeffersons when it was on TV.

Well, we're moving on up, moving on up to the East Side.

And on East 85th Street, in that iconic high-rise featured on The Jeffersons, there lived a handsome doctor and his beautiful wife, a young couple with their whole lives ahead of them.

From the outside looking in, Robert and Gail Birnbaum should have been the perfect couple.

Tell me about your sister. What was she like?

Gail was a very gentle soul. She was sensitive. She was loving. She was creative and gorgeous in that damsel-in-distress way. My sister Gail, Beth Katz, was the first child in our family of 3 children, born on March 8th, 1956. We were all living in Brooklyn. I was 1 year behind Gail in school. We were best friends. We lived that idyllic, carefree life. We walked to the penny store. We could chalk the street and play hopscotch. When she was in 4th grade, my parents moved to Long Island. That was really exciting for us. All of a sudden, Gail and I were going further than the candy store, into the city, to Broadway shows. It seemed to us to be a very normal childhood.

This is my yearbook from high school. That's Gail. That's me on the same page. Gail was on the honor roll. She was so smart, so bright. She was soft-spoken. and yet very powerful presence at the same time. She was a very special person.

She was beautiful, smart, and unfortunately anxious. There was a little bit of a depression early in life. She never thought she was good enough. She never knew how good she was.

After high school, she went to the State University of New York in Albany. While she was there, She fell in love with a musician in a rock band.

I don't think I've ever seen Gail so happy. Gail fell head over heels. She was going to design the costumes for the band.

Gail moved to Manhattan to pursue a degree in dance at New York University and to try to help her boyfriend land a record deal.

Gail's a single, gorgeous woman in Manhattan, bartending, meeting rich and famous musicians, record executives, and the relationship ends.

Elaine says things went downhill for Gail from there. She has an arm injury, drops out of school, and is drifting without a purpose. It all comes to a head on a traumatic night in 1979.

On a night that I'm supposed to meet her, I get a call. She's in the hospital. She's tried to commit suicide. In my heart of hearts, I believe it was more of a really, really big cry for help than a true suicide attempt. How did Gail recover from that experience? She didn't.

Over time, Elaine says Gail appeared to bounce back, landing a job at an ad company and building her way back up.

And that's when one of her friends decides that she's got to introduce Gail to Dr. Robert Birnbaum.

Robert Birnbaum grew up in West Orange, New Jersey. It is upper middle class, very nice area. His father was a physician.

Attended the local high school, where he was brilliant. He was always interested in flying, and in high school, He got a pilot's license and was allowed to fly out of a number of small airports dotting northern New Jersey. But he decided to pursue a career in medicine, following in his father's footsteps. He graduated from Albany Medical College and was a surgical resident at the time he was introduced to Gail.

He's close to her age, Jewish, classical guitar player. He spoke several languages. He was a gourmet cook, an expert skier. He wasn't just a pilot. He had mastered instructor-level piloting.

He loved to fly, and one of the first dates that he took Gail on was a flight around Manhattan, you know, in the evening, on the skylight and everything. She was so enamored with this.

It was magical. It was romantic. They could go anywhere. You know, they'd hop on a plane, go to a beach someplace. She had her private pilot chauffeur, and Bob loved being in control. So this was a place where Bob really got to shine.

However, in spite of all of his pluses, there were problems with the relationship, and it was obvious early on.

There were red flags when we would be together. With them as a couple, he would be very controlling of her. Even if she had to go to the bathroom, he would be like, where are you going and when are you coming back?

The first time I went on a double date with the two of them, the four of us are in a sushi restaurant and Bob starts using chopsticks and picking up and shoving it in my sister's mouth. It was so odd. I was so embarrassed. And then he starts doing the same thing to me.

He starts feeding you?

He starts feeding me. It was so uncomfortable. He was such a weirdo.

But Gail had made up her mind. Bob was marrying material, and the two get engaged. But then, all of a sudden, those red flags about Gail's seemingly perfect fiancé Become 4-alarm sirens.

And I get the hysterical call from my sister. She gets into the car holding her little cat in her arms, crying. Bob tried to kill the cat. What do you mean?

By August of 1982, Gail Katz was flying high, engaged to her Pilot boyfriend Dr. Robert Birenbaum. Her mother couldn't have been happier.

Voilà, here it is. Young Jewish doctor from New Jersey is marrying her. What could be better?

That's how he seemed on paper. In reality, the more I got to know him, the more I realized he was very awkward, very controlling.

During the summer, Of '82, I get the hysterical call from my sister. I must come into the city. I must pick her up. She gets into the car holding her little cat in her arms, crying. What happened, Gail? Bob tried to kill the cat. He had the cat in the toilet, choking it with its head. Submerged underwater.

He was offended because she seemed to love the cat more than she loved Bob, and so he wanted the cat dead.

No, no, no, Elaine, we're gonna get rid of the cat, and then everything's gonna be fine because he's gonna believe that I love him. And I'm like, no, not really. You really have to get rid of Bob.

It turns out that this wasn't the first Earlier in their relationship, he had told a story about having accidentally, in his words, strangled a prior girlfriend's cat. Her cat got loose in the car, and he said he strangled and killed that cat in the car.

This is nuts. This is scary. And I'm like, you know, he's done this before. It's not about loving a cat. It's not about you loving the cat. It's about being violent. No, no, no, no, no. You know, she had 2 years of a psych degree. She knows better. I'm like, I can't believe you're marrying this guy. And I was sworn to secrecy. I never told my parents.

In spite of this extremely upsetting incident and warnings, Gail and Bob were married August 29th, 1982, in a Manhattan synagogue.

She's wearing a white dress. She's gorgeous. She was happy. We had great champagne. We had, you know, a great band. But Bob was awkward. Bob couldn't dance. Bob doesn't drink. My sister told me, I'm smart, I'm loving, my love will cure. This is going to work out.

The newlyweds enjoy an idyllic honeymoon on the island of Crete. When they get back to New York, they continue trying to live in an upper-class They are doing ski trips.

There's beach vacations in the Caribbean with other couples that are doctors and their wives. She enjoys that.

He also was still involved heavily with his passion of flying during that time. Whenever he could get a chance, he would head over to Jersey. That's where he rented the plane.

They, in January of '83, moved into a 2-bedroom apartment 12th floor apartment at 185 East 85th Street, a building actually that America knew from The Jeffersons sitcom. This was making it for them.

He was a resident doctor. He didn't have a lot of money. How could they afford this?

Bob's parents paid the rent.

After they got married, he was in a residency at Maimonides. He was working very long hours with the intention of opening someday his own plastic surgeon practice.

Back in the '80s, I worked at Maimonides Medical Center in Brooklyn, where I met Bob Birnbaum. Bob was socially awkward. He was socially awkward with the patients as well. He did not have a connection with the patients. I think he was very into himself, and I don't think he was really interested in his appearance all that much. He would have his pants halfway down in the back, very wrinkled shirt on.

Gail was an undergraduate finishing her BA, taking classes at Hunter College. Money was tight, and Gail decided that one way to make it was to try to be a personal assistant to women living on the Upper East Side. And so she put out an ad.

I responded, and, you know, in no time she was working for us.

Francesca Beale was a high-powered attorney at CBS TV at the time, and She puts Gail to work as her assistant.

She was beautiful. She was delightful. Everyone who met her said how wonderful she was. She glowed with happiness at that point.

Did she ever talk much about her husband?

Not much, but when she did, it was in terms that I would say were affectionate and that she was proud of him.

To people on the outside, it might have looked like the perfect couple had the perfect life in the perfect spot. But the reality was a lot bumpier than that. They were fighting a lot.

Dr. Birnbaum's controlling nature was the prime mover which caused the tension in the marriage. He wanted to control every aspect of her life. There was always screaming and fighting going on in the apartment.

She came to my apartment to study because she didn't feel comfortable staying around the house. She would complain that he was verbally abusive, that he would put her down, undermine her all the time, tell her she wasn't any good.

She lived by these laws he set up. She had to be home by a certain time. She had to dress a certain way.

My sister would go to turn on a light. He would literally hold her hand as she's moving for the light, and with his other hand, turn the light switch on. There wasn't a thing that was too small for Bob to control.

I had a 30th birthday party in a restaurant, and Bob and Gail were there. Bob insisted that she sit on his lap through the dinner, and at some point, I think that she was feeding him his food. I said, Gail, why don't you sit down? Sit down in your own seat. And she seemed intimidated. She said, no, no, this is okay. It's okay. I just got the feeling she didn't want to cross him.

By the end of the year, she is certainly complaining to others. Bob is never home. She's lonely. This is not a happy marriage. And then it was like a house of cards.

That house of cards would soon start to collapse following a shocking outbreak of violence.

Bob sees her smoking. Leaps over a couch to get at her as quickly as possible.

And it would all lead to an alarming letter warning of imminent danger.

I wish I had known about that letter so way before. I think I would have scooped her up in my arms and taken her home.

On the surface, Robert Bierenbaum and his wife Gail seemed to be the perfect couple. young, attractive, with a bright future. But behind the walls of their Upper East Side Manhattan apartment, the relationship had turned toxic.

Their marriage went into a downward spiral of constant arguing, fighting over just about anything. Like a neighbor told us, like cats and dogs And it was constant.

She definitely told me she was not happy. He'd pay attention to her, but more in the way of watching her, watching what she was doing, who she was talking to. He really was a cold guy.

Bob had rules, and you better follow those rules. Bob had this thing about smoking. Nobody should smoke because it's bad for their health. Back in November '83, my sister was studying for her graduate record exams, her GREs. She thought Bob had left to go to work that day. She was feeling nervous, and as she tells it, she went out on the balcony to smoke a cigarette. The door opens and he smells the smoke, and he literally leaps over the railing Living room furniture, strangles her to the point of unconsciousness, then revives her and apologizes, saying that it would never happen again.

Gail would have gone into the 19th Precinct, and she reported the incident to a police administrative aide. If this had happened in 2021, Robert Birnbaum would have been in handcuffs. The fact that this was 1983, nothing was done about it.

This time she doesn't say, oh, he just loves me. This time she says, you're a sick bastard. Go get help. I am not staying in this marriage unless you get help. And Bob goes to see a therapist, Michael Stone.

After Gail charged that her husband, Dr. Robert Birnbaum, had tried to strangle her in a rage, So in the course of looking at the case, you know, I find Dr. Stone and I interview him. At the end of seeing him, did you have the impression that he was under control?

No, I had the impression that he was not in good control. The more trivial the incident that sparked it, in my way of thinking, the more potentially dangerous the person. This was a minor incident, which means that he had a hair trigger He says, I realized she was not going to be safe living with him.

And he tells me, I wrote a letter memorializing this. It's a letter of warning to Gail.

The letter went as far as being a hold harmless letter. He didn't want to be held liable for not warning her about the danger.

The letter says, I have been advised by Dr. Stone That for reasons of my own safety, I should at this time live apart from my husband, Dr. Robert Birnbaum. I further understand that if I do not heed this advice, I must accept the consequences, including the possibility of personal injury or death at the hands of my husband, and absolve Dr. Stone of responsibility for any such eventuality.

This letter says that you are worried about her husband killing her. Yes. And that you're trying to warn her. That's right. Have you ever written a letter worded that strongly to or for another patient?

It's the only letter I've ever written to a patient of any sort in all those years.

When she left your office the last time she left your office, did you feel then, even then, that she was in serious danger? Yes.

Rather a sinking feeling about the future because I had warned her every way I knew how, and she wasn't heeding my warning.

When Gail got the letter, I know that she— of course she kept it. She didn't just destroy it or read it and throw it away. She put it away.

Were you aware of the letter?

Gail told me about it approximately a year after she got it. She's like, it says he's a psychopath and that he's going to kill me.

Why in the world would she stay with this guy after she received that kind of warning?

I think she didn't believe it. No, no, no, Elaine, you know, I'm just about finished with my PhD. I understand psychology. I'm safe. Don't worry about it. She said to me that, I'm— I want to get divorced. You know, he really has to do right by me, and if he doesn't, I am going to publicize this.

After she received the letter, I mean, the marriage continued. They continued living under the same roof.

The situation was calmer at home, but it was the calm before the storm. It was all going to blow up for them come the 4th of July weekend.

I called my mom, and she said, do you know where Gail is? And I said, what do you mean, do I know where Gail is? I think something terrible has happened to her.

Gail has suddenly gone missing, vanished into thin air. Could that ominous warning in Dr. Stone's letter have come true?

And my heart went into my throat, and I said, he killed her. I knew it. I knew it right away.

New episodes The dynamic in the relationship, I think, changed dramatically after the strangulation incident, to the extent that she would go to bed fully clothed.

We're talking about people who are in the 3rd year of their marriage, and they're not having sex. Gail admitted to me that she was dating a little bit. She told me how lonely she was.

On July 6th, 1985, we took a walk. She liked to hang out by the Metropolitan Museum of Art. We sat down and we talked. talked, and she had a copy of the real estate section of the New York Times with her. She said to me, I'm gonna look for apartments and I'm gonna tell Bob that I'm leaving him. It's like, yay, thank God she's gonna leave him.

Sunday, July 7th was a turning point in this story. Sometime that morning, Francesca Beal A sometime employer of Gail called.

I had not been in touch with Gail for a long time, and she was extremely happy to hear from me.

But it turns out Francesca wasn't calling for Gail at all. She wanted Gail to ask Bob for a referral to a doctor.

She didn't seem angry, but she just seemed quiet and sad.

It sounds like she was deflated. Yes. It wasn't about her, but rather Yeah. The doctor husband.

And maybe she thought I needed her for a friend.

It wasn't quite the phone call that Gail was looking forward to. What we do know for certain is that something sparked another argument. And we know from their downstairs neighbors that the argument was loud and it continued for a while until there was silence.

Later in the day, Dr. Birnbaum left the apartment, showed up in New Jersey at the birthday party for his nephew, where he was telling people that she had left the apartment in a huff. He doesn't know where she went. He hasn't seen or heard from her since she left the apartment, and he was worried about her.

I call my mother, and my mother says, do you know where Gail is? And I said, no, I don't. And I'm like, no. And she's like, Bob called. They had a fight this morning, and Gail never came home.

Bob calls me. He says, is Gail still with you? I said, what do you mean, is Gail still with me? I left her yesterday at 5 o'clock. My heart went into my throat.

She's not with me. And she's not with my parents. And at that moment, I know that my sister's dead.

I just put the phone down for a second. I said, he killed her. I knew it. I knew it right away.

And if she's not alive, there's only one person who is a likely suspect. to murder her, and it's Bob. There's no other suspect.

On Monday, July 8th, 1985, about 9 in the evening, Robert Bierenbaum came into the precinct to report his wife Gail missing. I interviewed him at length. Robert mentioned that sometime that morning, Gail and he had an argument. She left to go to Central Park to cool off. She was dressed to go lay out in the sun, pair of shorts, I believe a halter top and a towel. And that was not unusual for Gail.

Bob tells police that they had an argument and she came here to the park?

Yes. And by the very following weekend, we had missing posters made of Gail. My family, and my sister's friends all came to the park and plastered—

This poster.

This poster. We plastered the entire loop of the park. We never spoke to a single person that said, I recognize Gail.

It was almost like pulling teeth to get Robert Birnbaum to help.

It was almost like they had to drag him Meanwhile, the tension is building between the Katzes and the Birenbaums. The Birenbaums are portraying Gail as a mentally unstable person who might be responsible for her own disappearance.

In front of us, they're saying to the police, she was suicidal, she must have killed herself. Yeah, now this is ridiculous. My sister has a therapist who says she's healthy. The other lie that he starts to float is that she was suicidal. is it must have been a drug deal gone wrong. My sister wasn't buying drugs on the street. They just kept floating alternate theories, and all of them defamed my sister.

A search was made, and every effort to locate someone that might have been a victim of a crime was made. There weren't any bodies. There weren't any victims that were discovered in the park. Gail was not discovered. She did not commit suicide in the park.

Weeks after his wife's disappearance, Birenbaum seems the opposite of a grieving husband.

I heard he was out in the Hamptons partying with a lot of elite people.

He's dating, he's bringing women back You know.

But then investigators make a shocking discovery at a New Jersey airfield, a discovery that could bring Robert Berenbaum back to Earth. They struck gold. This was a bombshell discovery. It was. It turned things upside down. Just weeks after his wife Gail vanishes in New York City, Robert Birenbaum starts spending time in an exclusive spot out on Long Island.

Gail and he had a share in a Hamptons house, and Robert continued to go out there on every weekend he possibly could. He was seen partying in a notorious disco in the Hamptons called Marrakesh.

Even his dress changed from L.L.Bean to Saturday Night Fever. This wasn't the concerned husband, and the summer house people thought that his behavior would just— was rather cold and dismissive of his missing wife.

Bob's coworker at his hospital, Karen Caruana, was also out in the Hamptons at the time. Some mutual friends suggest that the two of them meet for a date, even though it had only been a few weeks since Gail went missing.

We went out to dinner. He drove back to this house. I remember sitting in his kitchen and asking him, you know, tell me what happened with Gail. And what he told me was, Gail had left and flown out to California and gotten some kind of a waitress job on the coast. He had hired a private investigator, and this private investigator had found her out there.

That wasn't true. What we know for a fact is, after having spoken to the investigator, that there was never any evidence of her in California.

I asked him, About the police. Have they gone and searched his apartment, et cetera? And he told me the police had already been there. They had already searched his apartment, and everything was clean.

That was far from the truth. The scope of our search in that apartment with the forensic team was limited to finding fingerprints on personal items that Gail may have come in contact with in normal daily activities. I tried to get a broader scope to get evidence of any crime, and that was objected to by Scott Greenfield, Robert's attorney.

How the night progressed. Okay. I'm not sure how we got up to the bedroom, but we did. And we had, you know, sex quite a few times that night. I kind of question now my judgment on, you know, doing that. And, you know, I had let my guard down, and that was probably not a good move on my part.

He told that lie to Karen Caruana because he wanted to sleep with her that night. This is a man whose wife has been missing now for weeks, and at the first opportunity he has, he's jumping at the chance to get into bed with another woman.

In August of 1986— so a year's gone by— the Manhattan District Attorney's Office decides to take a look at the case, and it goes to the chief investigator, Andy Rosenzweig. Andy Rosenzweig is a criminal's worst nightmare because he's extraordinarily intelligent. He's extremely detail-oriented. But when you looked for a case, what did you look at in the folder to say, this one looks like it could go?

Well, we looked at a case that, you know, presented a challenge that we thought perhaps other agencies wouldn't be equipped to do as well as us.

What Andy Rosenzweig did initially to further this investigation was that they knew he was a pilot, and they began canvassing various airports to see if they could find any Evidence as to whether he had rented or flown a plane on July 7th, 1985.

They started out looking at private aviation companies in New Jersey. The second choice was Essex County Airport, and they struck gold. So they came here, went through that door. Went through that door, and they said, yes, as a matter of fact, we do know Robert Birnbaum. Do you have records of him flying? Yes, we do. Robert Birnbaum, the day his wife disappeared, drove to Caldwell Airport sometime in the afternoon, flew a plane for over an hour and a half, returned to the airport, and then went to his sister's house for the party. Bombshell discovery. It was. It turned things upside down. He spoke to detectives and he told them, I stayed at home till 5:30, when he, when he knew that by that time he was already probably 75, 80 miles out over the Atlantic Ocean. Once they figured out he had gone up in the plane, how quickly did they say that was where, how he disposed of the body? That was immediate. The working theory was that he folded her up, put her in a duffel bag, came out to where we are today, rented his plane, loaded her in the plane, flew out over the ocean, and dumped her in the ocean.

My parents and I are like, great, we've got that missing link. Now we can prove he did it.

The existence of the airplane, the existence of the flight, It was all suggestive and circumstantial. So the DA's office at the time felt we don't have a murder case.

And I remember the district attorney's office bringing my parents in and saying, it's not enough.

How hard was it on your parents?

It was a death sentence for my parents.

Then in May of 1989, 3 years after the investigation goes cold, there's another heartbreaking development for Gail's family.

A torso washes up off of Staten Island, headless, legless, and armless.

We found these X-rays, and an X-ray technician compared this X-ray with this torso and said, this is Gail. Now we have a body to bury. We have some closure.

While the discovery of the body still isn't enough for the police to press charges, Elaine's crusade to hold Gail's husband accountable hasn't been laid to rest. Elaine Katz was determined to get justice for her sister, and that meant staying after Robert Bierenbaum.

I would send clippings to the doctors that he worked with, to the people that lived in the building, and I would leave messages on his answering machine, you know, telling the woman he was living with, he's dangerous, you know, be careful.

Your intent was—

Well, my intent was to make every day of his life miserable, to make him walk down halls and have people think, oh my God, he's a murderer.

Elaine's relentless efforts appear to pay off. In 1989, Robert Birenbaum pulls up stakes and leaves New York City behind.

I believe that I ran him out of, of New York.

But the next chapter in the Bierbaum saga would come as a complete surprise.

You are all I long for.

A startling new life and yet another transformation. Apparently had undergone quite a makeover, and they started wearing fancy suits.

Yes, he loved his Armani suits.

Sometimes, though, it's not so easy to bury the past.

The rumors started coming out. in from New York that Bob potentially murdered her.

Feels completely safe, completely confident that he's gotten away with murder.

Robert Birenbaum had absolutely no idea what was coming.

What was coming was a startling demonstration in the sky, one that could prove the key to clipping Dr. Birenbaum's wings for good.

I don't think Spielberg could have done it better.

Her disappearance made headlines in New York in 1985. Gail Birenbaum vanished from the apartment she shared with her husband, Robert, a Manhattan plastic surgeon.

Turn on the TV. They've arrested Robert Birenbaum. Bierenbaum for the murder of Gail Katz. I started screaming. Dr.

Bierenbaum, we have to ask you, did you kill your wife?

Bob Bierenbaum is the last person anybody would think that would commit a murder unless you saw his other side. My life was flashing in front of my eyes.

He was moving all over, maybe to get as far away from New York as he could.

After he left, I'm confident that he thought the ballgame was over.

I didn't want him to get away with it. I wanted every day of his life to be miserable.

I said, were you ever married before? I thought, whoa, I touched a nerve.

Did he do it? Could he have done it?

Could it have been me?

The first thing that stood out to me were the flight records. Oh my God, there's the explanation. Why Gail is not around anymore.

I didn't want anyone to dig her up.

Literally, they're going to have to exhume the body they think is Gail's.

I am so devastated.

What was in that grave?

He has no idea what's coming down the road, and it's us.

Las Vegas in 1989, 1990, there was a whole new energy occurring. We had dazzle, lots of glitz, lots of beautiful, beautiful showgirls, cocktail waitresses.

Plastic surgeons were starting to flock here. This was the wild, wild west.

It was a feeding frenzy for plastic surgeons.

It was December 31st, 1989. I decided to have a New Year's Eve party. It was a huge party, and my boyfriend wanted to bring a new plastic surgeon in town.

I went around the corner to the party, and we were having a good time, and somebody introduced me to Bob.

Your first impressions of him?

I thought he was very nice. He was tall. Dark and handsome.

It turns out Bob is none other than Robert Bierenbaum. He had been the target of an investigation in New York City after his wife Gail had gone missing in 1985 under highly suspicious circumstances.

Bierenbaum was a suspect because the police discovered that he had lied about where he was. They found out that he had been up on a plane, and he had never mentioned it.

The DA's office had closed their end of the investigation without bringing charges.

I didn't want him to get away with it. I wanted every day of his life to be miserable. I believe I ran him out of, of New York to Vegas.

In Las Vegas, Birenbaum transforms himself from a surgical resident in New York to a hotshot plastic surgeon. He befriends colleagues like Dr. Julio Garcia, the man who reattached Evander Holyfield's ear after Mike Tyson bit it off.

Keep your eye on Mike. See, Mike has just— see, look at him.

We all knew he was from New York, but he, he played that card close to the chest. He did not disclose any chips on that table. He, he kept his secrets to himself.

He called me up and asked me, do you want to get high tonight? And I really didn't know what he was talking about.

And suddenly you were here, huh?

Yes, this is the airport. flying on our first date.

Fly me to the moon.

It was fun. Las Vegas is fun to fly around at night with all the glitz and lights.

In other words, oh.

The first year was perfect. Fun, fun, fun. We went to social events all over town. We went to medical black-tie events. We went on a lot of ski trips.

Vegas Bob 2.0 was certainly new and improved from the New York version he had left behind. He had traded in his wrinkled plaid shirts for Armani suits.

He had a way of taking an Armani suit and making it look a little sloppy.

He had a sports car and a Jeep truck.

Las Vegas, we're big on vanity plates, so why wouldn't he have Nip and Tuck and Nip and Truck? It's the way we roll here in Vegas.

In Vegas, there was another side that emerged to Bob. And that was a charitable side. He joined a group called the Flying Doctors, which several times a year would fly down to a specific community in Mexico and provide medical care to poor families.

Bob was a perfect fit for this, especially being a plastic surgeon doing cleft palates. He changed these children's lives forever. I loved going to Mexico and doing that work. It was kind of a glue that held us together.

She did call me and said, you'll never believe it, but this guy flies to Mexico and helps children that are disadvantaged. I can't even believe I met a person that was so great.

But one thing Dr. Bob hasn't been so eager to share with Stephanie are details of his previous life in New York. Stephanie says she found it odd that he was so reluctant She was asked to have his palm read by her close friend, a palm reader.

He had this dark energy, and his eyes, they were the strangest thing that I've ever seen.

His eyes would go like this.

Well, by then he figured out what I did for a living, and so he didn't want to have anything to do with me. There was something secretive about him.

Luggage tags that said Gail Barenbaum on them. So I'm like, OK, maybe a cousin, no biggie. And then after a while, I'm just like, Bob, who's Gail Barenbaum? And then it took him a long pause. And he got kind of emotional. And he told me he had been married before. They had a big fight, and she took off for Central Park, and she disappeared.

Stephanie says Birenbaum told her he had been thoroughly investigated by the cops and cleared of all wrongdoing.

The way he told the story, it was believable. About a year and a half into the relationship, he gave me a fortune cookie. And I opened it up, and there was a diamond ring. And I'm like, Bob, we can't get married. Because Bob wanted kids. I did not.

So that's when our trouble began. Bob's image on paper was real, but cracks started to appear.

One time we went flying when we went down to Sedona with Dr. Thalgott. It was a very intense landing.

She simply bumped the door of the airplane when it was parked. Demeanor changed just like that and went into a rage. Tight eyes, tight mouth, focused, red in the face, screaming. I thought he was going to strike her. I thought, this guy's crazy.

On another trip, this time on a boat, Stephanie says she feared for her life. There was an explosive incident after she asked the host for a glass of red wine.

When he went to open that bottle of wine, it was like opening a bottle of champagne that sprayed everywhere. Bob went ballistic. That's when I saw his laser eyes that just pierced my soul. He just raged on me like it was my fault. And I thought, ooh, this is not good. My life was flashing in front of my eyes. That was like a tipping point in our relationship.

Alarmed by that incident, Stephanie says she demanded they see a therapist, just like Gail had done a decade before.

We only had one session, and she goes, there are issues there, that my life could be in danger with him. And so I started to build a strategy to leave.

I definitely said, Stephanie, you dodged a bullet.

But Birenbaum quickly bounces back, dating and proposing to one woman after another.

Bob took the same diamond and set it in one ring after another after another until Bob finally met the woman of his dreams, Janet Cholette, a gynecologist in Las Vegas. And in June of '96, they were married.

There would be a next stop and yet another transformation for Dr. Bob when his wife gets offered a new job out of Las Vegas.

I learned that he was in some real rural place. Sounded like the antithesis of New York City life.

But it turns out Dr. Bob was about to become a hero after a terrifying incident.

The tiger reared up on his hind legs.

Minot, North Dakota is known as the Magic City. That dates back to the early days when the railroads came through and a city emerged out of the prairie and grew like magic. But when we talk about the Magic City today, the magic in Minot is the people, how friendly everyone is and willing to do something for a complete stranger.

People tend to just accept you and not ask a bunch of questions. If one was escaping something, perhaps that's a great place to go.

Robert Birnbaum came to Minot in the mid-'90s and made quite a splash.

When Bob was in North Dakota, there were, I believe, 5 plastic surgeons in the entire state.

Bierumbach had followed his wife Janet from Las Vegas to Minot after she landed a job there. They both worked at Trinity Medical Center— Janet as a gynecologist, Bob as a plastic surgeon. They lived in a small condo.

First time I spoke with him, uh, he got real close, you know, kind of got into my space and touched my face because I had a mole on my face. And I'm kind of backing up, and he says, I can fix that.

He didn't quite fit in.

His style was more New York than it was Minot, so he stood out. But he made an effort to be part of the community.

The Jewish community was very small. We all knew one another. I started a bagel shop in Minot. He was a customer sometimes, and he was also well known in the community for making his own bagels. He always came across as being a nice, kind of disheveled, not quite put-together guy, you know, and smart.

People in the medical community were impressed with him. He had great credentials.

I think people in Minot would have imagined that Dr. Bierenbaum was a kind of gift.

Then on July 30th, 1998, there was an incident at the North Dakota State Fair that thoroughly cemented Bierenbaum's reputation in Minot.

Every year, our biggest event in Minot, in North Dakota, is the North We're at the South Dakota State Fair. You've got rides and carnivals and every kind of food imaginable.

Okay, let's hear it for Mackenzie, our tiger tamer.

There was a tiger exhibit at the fair. They were offering pictures on a table with a cub tiger.

We had been extraordinarily busy. We had a vast, large attendance on the day. In the photo ops, a cub was being fed a bottle of milk And all the tigers had been overfed at that point except for a roughly 280-pound tiger named Lutan. And I thought we were coming up to a break, but, you know, the manager said, well, let's get this one family.

The tiger Lutan was a last-minute substitute for this photo.

It was taken with Ron Gaddis's family gathered The trainer had the tiger by the leash, and the tiger was reared up on his hind legs, pulled my son back towards him into its mouth, and commenced making a chew toy out of my son's head. My son was a fraction of an inch from losing his right eye and a quarter of an inch from losing his left. from losing his left ear. They were expecting to have to fly my son medevac to Fargo, but there just so happened to be a plastic surgeon that they were able to get a hold of, and it happened to be Dr. Berenbaum. He sewed his eye back in and tucked it nice and tight and, uh, put his ear back on. I believe Dr. Berenbaum saved my son's life. Without a doubt, hands down.

While the incident with that tiger makes Birenbaum a local hero, he's apparently still touchy about details of his past life.

I just in passing sort of said, were you ever married before? His reaction was so immediate and so, um, stiff.

Surprised, shocked, you know, that I thought, whoa, I touched a nerve.

Soon after arriving in Minot, Janet decided to go to law school, and she moved to Grand Forks, North Dakota, which was 200 miles away.

He had his domestic situation with a wife in Grand Forks, but he had a patient base in Minot.

He got into his plane and flew. Between the two cities. He'd be working in Minot and then see Janet on the weekends. In November of '98, Janet and Bob had a baby daughter.

My name is Barb Cooper, and I was one of the nannies for Robert Bierenbaum and his wife Janet in Grand Forks, North Dakota. It looks like he must have come home from work. He had his suit on and just sitting down on the floor Kitchen floor, just right where he was, and to play with his little girl and his dog. This is one where Bob would have come home. He's got a name tag on. Just his face would just light up when he would see her. He looked good, wore suits, loved his child, loved dogs, you know, just all overall things that you would think would be great characteristics to have in somebody.

He becomes a family man, has a daughter.

He has a child.

At that point, do you think he may well live out the rest of his life never having to pay for this?

I think I began to feel, even in Vegas, that that was the life we were going to have to live.

After he left Las Vegas, and moved to North Dakota. I'm confident that he thought the ballgame was over, that he's never going to have to deal with this ever again.

And then one day, something really strange happens while you're at work.

I had a strong, loud knock on the door.

I opened it up. There were a couple gentlemen standing outside. They wanted to talk to me about Dr. Robert Baer.

He has no idea what's coming down the road.

One of the stops on that road would be the cemetery where Gail was laid to rest. And what they'd find in her grave would surprise everyone. In North Dakota, Robert Birnbaum has created a new life for himself as a highly respected doctor and a pillar of the community.

Dr. Birnbaum was a guy who did good stuff. In New York, he'd be called a mensch. Here, he'd be called a good guy, somebody that you might think is a little bit odd, but you appreciate because of the good deeds he's doing.

While Bob was building a new life in the Dakotas, back in New York, there was somebody, somebody important, who couldn't forget the disappearance of Gail 14 years earlier. That guy was Andy Rosenzweig, the chief investigator of the Manhattan District Attorney's Office.

How long did you guys work at this on the first go-round?

Probably between 9 and 12 months.

As Andy Rosenzweig is getting towards retirement, he's also looking at cases that are still haunting him, and the Berenbaum case was top among those.

Within the DA's office, they had just created a cold case unit, and Rosenzweig decided to give this cold case to Steve Sirocco and Dan Bipp, 2 seasoned investigators who he knew if anybody could find out if Berenbaum did it, it would be them. They would.

Andy came to Steve and I with a file and said, I want you guys to take a look at something. The first thing that stood out to me when I reviewed the file were the flight records. Oh my God, he flew for 2 hours the day his wife disappeared. And the fact that he doesn't tell anybody— there's the explanation why Gail is dead.

That coupled with his visits to his psychiatrist, Dr. Michael Stone. His sessions with Dr. Stone were so intense and upsetting, the psychiatrist was ethically bound to send his wife, Gail, a letter that warned her that she was in danger of her life.

The letter says, if I do not heed this advice, I must accept the consequences, including the possibility of personal injury or death.

I called Stone, cold-called him, and I said, Dr. Stone, my partner and I are reinvestigating the disappearance of Gail Katz Birnbaum. And he said, of course he killed her. Dr. Birnbaum's a dangerous psychopath. This case has been burning on my brain. Then I said to Dan, the next day, I think we're onto something here. And that's when we started, like, rolling.

Andy Rosenzweig calls me, and he says, I want to reopen the Birnbaum case. Gail's case, and I had mixed emotions. I did not want my life turned upside down. I didn't want the wound opened for nothing.

And for Elaine, it would become even more difficult. Back in 1986, a female torso that washed up off Staten Island had been identified as belonging to Gail. Her family laid it to rest. in a cemetery in Queens.

In the summer of 1998, we decided to attempt to get Gail's body exhumed.

Body had been tended— been identified through an X-ray. Of course, we had the technology now to do DNA, and to our surprise, it came back that Gail Katz had been eliminated as a contributor I am so devastated.

That little, little shred of closure that I had has now been ripped away. And I looked up at Dan and at Steve, and I said, I don't know what to do. I think we all knew what to do. Now you better get a conviction.

Bibb and Sirocco decide to reinterview everyone associated with the case in person, including a woman Birenbaum dated in New York City after Gail's disappearance.

One of the things she related involved a phone call that came in the middle of the night, the police call from the Port Authority bus terminal. thought that they had found Gail. Bob's initial response is, can I talk to you in the morning? He hangs up and he says, I doubt it's Gail. Go back to sleep.

Bibb and Sirocco also traveled to Las Vegas to interview the women Birenbaum dated there. You get a knock on the door, investigators wanting to know about your old boyfriend.

They were from the New York Investigative Bureau.

You must have been blown away.

I was shocked. Last thing I expected.

In late November of '98, we decided to send investigators to North Dakota to see if we could get some kind of statement.

He's feeling as safe as you possibly can. All of a sudden now, he sees these guys from Manhattan. telling him, we're here because we're investigating, reinvestigating your wife's disappearance.

Dr. Berenbaum reacted with shock and disbelief. It was a baseball bat upside his head.

Then in September of 1999, 14 years after Gail's disappearance, a grand jury indicts Robert Berenbaum for second-degree murder.

Authorities accused the plastic surgeon of killing his wife Gail in this apartment, packaging her body, and dumping it somewhere over the Atlantic.

Manhattan DA's office— To see your boss's face on the 10 o'clock news accused of murdering his first wife was pretty shocking. When that came on, I was standing and I actually dropped to my knees. I was just like, I couldn't believe it.

Never in a million years you'd think you'd be using cold, calculated murderer in the same description as this guy, Dr. Berenbaum. There's just no way.

The Berenbaum story, when you get right down to it, is Dr. Jekyll and Mr. Hyde, and that's a hell of a story.

Robert Berenbaum will be returning to New York City, this time to stand trial for Gail's murder.

But with no body, no physical evidence, will he We knew it was gonna be the toughest trial that we, we'd ever had. There was no foregone conclusion to this case by any stretch of the imagination.

And there was a huge unanswered question that would involve a demonstration in the sky. Was it even possible to toss out a body out of an airplane flying at more than 100 miles an hour?

44-year-old Dr. Robert Birenbaum's dark secret has made national headlines.

Birenbaum turned himself in to New York police this morning.

I get a phone call from my sister. She says, turn on the TV, they've arrested Robert Bierenbaum for the murder of Gail Katz. And I started screaming.

Authorities accused the plastic surgeon of killing her in the apartment, packaging her body, and dumping it somewhere over the Atlantic during a 2-hour flight in his private plane.

It was such an unusual case. What doctor pushes his wife out of a plane on the— from the Upper East Side?

I delighted and And happy that this day had come. I, I saw my mother, father, and sister cheering up there. Bob, why don't you tell the public that you're innocent? Why don't you tell me that you didn't kill my sister? 15 years I'm waiting to hear you say that you didn't kill my sister. It's the moment that I was waiting for, that Bob knows he didn't get away with it. You were going to stand trial for my sister's death.

Dr. Birnbaum, we've been trying to talk to you. We'd spent a lot of time digging into this story, and I wanted to ask Dr. Birnbaum in person, point blank, did you kill your wife?

I have no comment, John. Thank you.

And, Doctor, you have nothing to say about this? You know, they've charged that you took her on an airplane.

He has no comment.

is in the middle of a prosecution. We'll say what we have to say in court.

We knew it was going to be the toughest trial that we, we'd ever had. No forensics, no eyewitnesses, entirely circumstantial.

On September 18th, 2000, there at 100 Center Street in Lower Manhattan, the trial begins. And on the bench, you have Judge Leslie Her reputation was no-nonsense, tough judge.

Well, it was an unusual case with a lot of difficult legal issues, and one of them would be, of course, that there was no body, because then you wonder how the prosecution is going to prove that there was in fact a murder.

In the opening statement, I tell the jury right off the bat, I have no forensic evidence, but I said nonetheless, it's going to point in only one direction— the guilt of the defendant in this case, Dr.

It was a key thing for the prosecution to let the jury see how Birnbaum had abused his wife during their marriage, including the 1983 choking incident where it was so serious that she lost consciousness.

Now, you would think that the prosecution has a huge card up their sleeves— that ominous letter from Dr. Michael Stone to Gail. It warned possible death at the hands of her husband. But it turns out there's a big problem with showing that letter to the jury.

The prosecution wanted to admit as evidence this devastating letter, but the real issue here was a legal one, and that involved the doctor-patient privilege. And I didn't allow the admission of the letter.

Although the jury couldn't see the exact letter, the witnesses— her sister, her friend—

were able to describe the letter, the Dan had done a terrific job of preparing me to testify. He says, you're going to be able to testify to more than I thought you would be able to.

It just helped the case to build and build and build. It was another factor that demonstrated the nature of their relationship.

Another critical part of the prosecution's case, the discovery that Birenbaum had flown his plane on the afternoon of July 7th, the day Gail went missing. Remember, he told police he was alone in their apartment during that time. Prosecutors, though, are able to show jurors Birenbaum's own personal flight log where the 7 for July had been apparently altered to an 8.

And not very professionally either. It looked like a child had done it.

A big hurdle for the prosecution was to persuade the jury that someone could actually fly a plane and push a body out the door and not crash.

And I was told by the defenders of Robert Bierenbaum, that actually doesn't work. You're flying this airplane at 100 miles an hour through the sky. You have the 120-pound victim, and somehow you're supposed to lean over and throw it— the physics of it just make it impossible.

We thought, what better way to show somebody it can be done than by doing it ourselves? We were going to find a plane, that model, and take 110-pound bags of dead weight and throw them out of the plane over the ocean.

The sergeant showed that Not only was it possible to dispose of the 110-pound bag, that it actually was very easy. He could do it either from the pilot's door, which he did, or from the passenger door. The trailing helicopter actually filmed the bag going into the ocean. I don't think Spielberg could have done it better.

I thought the demonstration with the airplane was extremely effective, probably one of the critical moments in the case.

But it turns out the defense has its own ace in the hole.

The defense has only one witness. If the jury believes him, it's a huge problem for us.

A bombshell eyewitness who threatens to overturn the entire case. Over the course of the trial, the prosecution calls 34 witnesses, including those close to Gail, who testify about how she had become fed up with her husband's treatment of her.

I talked about his controlling behavior, and I talked about the fact that she was looking for another place to live. She was going to leave. It was imminent. And I think that that was part of the reason why he did what he did.

The defense used cross-examination effectively to tarnish the reputation of Gail, to portray her as unstable, a risk-taker.

The defense did go into other reasons why she could have gone missing other than her husband murdering her. They brought up mental health issues that possibly possible drug use or infidelities.

Ultimately, I think what they did led nowhere. The evidence didn't amount to anything.

The defense had one witness, Joel Davis, and I think they pinned their hopes for the entire case on him.

Joel Davis was a retired textile manufacturer who told police early on that he had seen Gail in an H&H bagel shop Near where she lived at 3 o'clock in the afternoon, standing there in shorts with a beach chair with a friend.

He essentially blows up the people's timeline as to when she was dead. If a juror believes that sometime 3 to 4 that afternoon that she's alive, that's a huge problem.

What hurt Joel Davis the most was his description of the woman that he saw in the bagel store, that she was large, statuesque, full-figured. So you'd lead him even further down the road. You're saying, like, she had a big chest? Yes, she was voluptuous.

Steve blows up, like, on poster board size, this photo of my sister, and I get to say, that's Gail. She was an A-cup. Um, she barely filled that.

I think everyone in the courtroom— and there was a lot of buzzing— that the defense case had gone down the tubes.

The message I wanted to deliver to them in summation was that he's the right person. He's the guilty party. One of my favorite movies is North by Northwest. Alfred Hitchcock, tale of a businessman caught in an international intrigue. The movie, there's a discussion of how to get rid of a body, and James Mason says, this matter is best disposed of from a great height over water.

That made it into my summation because I thought it was entirely In their summation, the defense tried to take the prosecution's case apart piece by piece. No physical evidence at all. The, the body out of a plane, nice, but just a theory. Gail's own personal behavior could have been a problem that led to her own demise.

15 years after Gail's disappearance, The case finally goes to a jury. After just 5 and a half hours of deliberation, there's a verdict.

Once everyone heard there was a verdict, it was very, very tense.

My heart is pounding. I can feel it in my chest, and I can feel the tension in the courtroom.

The foreperson stands up and says, yes, we the jury have reached a verdict. And then the foreperson said, guilty. And there was a buzz in the courtroom.

It was just a sense of complete satisfaction for not only justice, but for the sister and the family. Guilty verdict against plastic surgeon Robert Berenbaum.

When you heard that conviction, your reaction?

I'll never forget squeezing my brother's hand and slamming it down on his thigh and saying, Guilty? With a question mark at the end, because did I just hear that? And then, of course, the reaction of my brother as he grabbed me and held me and we trembled and we cried. Then I knew it was true. I was in shock.

To finally see the handcuffs go on his wrists, to finally see him walk into a jail cell, The feelings are indescribable.

A typical sentence for me would have been 25 to life because of the enormity of the crime.

But there are very few cases in which someone has been a law-abiding citizen and has done good things. So I gave him 20 years to life.

Since that sentence in 2000, few people thought they would ever hear about Birenbaum again. But just recently, shockingly, Birenbaum would re-emerge, and what he would say would stun everyone involved in the case.

And I was like, holy shit, are you kidding me?

The earth shifted.

Since 2000, Bob Bierenbaum has been behind bars serving that sentence of 20 to life.

When Bob was incarcerated for many, many, many years, I stopped thinking about him.

Bierenbaum offered no apologies. to the Katz family when he was sentenced, insisting he was innocent. And he spent the first 10 years behind bars trying to prove his innocence and get his verdict overturned. He appealed in state courts, federal courts, got nowhere.

Back in North Dakota, there are still those who believe he might not have been guilty of the crime.

It didn't add up. You didn't think it would be possible for Somebody that nice to do something that, that ugly.

Just last December, after 20 years behind bars, Bob Bierenbaum was up for parole. Parole board denied him freedom.

There was no public reason given for the decision, but 20/20 obtained this transcript of that parole hearing. And in it is a shocking revelation. For the first time in 35 years, Birenbaum finally admits to killing Gail. To the parole board, Birenbaum said, I wanted her to stop yelling at me, and I attacked her. When he's asked, how did you attack her? He responds, I strangled her. Birenbaum goes on to say, I went flying. I opened the door And then took her body out of the airplane over the ocean.

I was stunned when I heard he admitted it.

And I was like, are you kidding me?

He admitted doing it just the way we told the jury that he did do it.

The earth shifted. I was in shock. He admitted killing Gail. And I cried.

He said he killed Gail because he was immature. and didn't understand how to deal with his anger. The parole board noted that at the time, he was a 29-year-old medical doctor.

And you were immature? Really? Said he was a danger to the community and needs to stay in.

When I read those minutes, oh my God, this is exactly the same man that I knew 35 years ago. He is incapable of a shred of remorse.

It's a very sad story because it's an unnecessary one, and this is what happens so often in domestic violence cases. The victim could have been saved.

This is the home of the Pace Women's Justice Center. 20 years ago, we named It's Gail's House, to raise awareness of the pervasiveness of domestic violence. The first time Bob strangled my sister to unconsciousness, we just—

So young, such potential.

I would like to believe that my sister's energy Has been out there for 35 years cheering me on. I feel my sister's spirit is here. It is warning others, inspiring others.

It's still to this day, I think about her constantly. So young, such potential.

I would like to believe I believe that my sister's energy has been out there for 35 years cheering me on, motivating me, encouraging me, holding me up. The world's a lesser place for the loss of my sister.

Some really moving words from her sister here tonight. And we should point out that Robert Bierenbaum's next parole hearing is scheduled for November He turned down our request for an interview.

And if you or someone you know is dealing with domestic violence, please go to our website at abcnews.com/2020 for resources that could help.

And you can find all new broadcast episodes of 20/20 Friday nights at 9:00 on ABC.