Netflix Docuseries Details Long Island Serial Killer

SPOILER ALERT: This story contains details about the Gilgo Beach murders case and details about “Gone Girls: The Long Island Serial Killer” docuseries, now streaming on Netflix.

Liz Garbus remembers exactly where she was the day she learned Mari Gilbert had been killed.

In 2016, the Oscar-nominated documentarian was at a dinner with a few journalist friends when she got the text from author Robert Kolker that Gilbert had been killed by her daughter Sarra during  the chaos of Sarra’s psychotic break. Garbus was in the midst of adapting Kolker’s book “Lost Girls” into a film, and had met Gilbert once a year earlier. The force-of-nature mother and activist left quite the impression — and was at the center of the story Garbus would be telling about a prolific serial killer on Long Island, New York who had not yet been caught.

“The whole dinner just kind of stopped when I mentioned it, because everyone was suddenly talking about what happened and all the layers and ripple effects of the case,” Garbus tells Variety.

However, the case the table was enraptured by wasn’t just Mari’s tragic end, but rather the chain of events set off by the disappearance of her eldest daughter, Shannan, back in 2010. At the time, Shannan had been working as an escort, and went missing after meeting a man near Gilgo Beach on Long Island. Her disappearance was met with little concern from authorities, who brushed off the case as another missing sex worker — until Mari’s persistence led to an investigation. Initially, they didn’t find Shannan’s body, though the search — when it finally began — turned up nearly a dozen other bodies in various states of decomposition and mutilation scattered across the area. The first four victims found and identified –– Megan Waterman, Melissa Barthelemy, Amber Costello and Maureen Brainard-Barnes, pictured above –– became the faces of the case known as the Gilgo Beach murders.

Shock and awe, as expressed by Garbus’ dinner companions, is how most people typically react to the twists and turns of the case, which she touched on in her 2020 film “Lost Girls” through the lens of Mari and her fight to find her daughter (whose remains were discovered in December 2011). After the film’s muted debut on Netflix during the early COVID shutdowns — the movie had the misfortune of dropping on the streamer on March 13, 2020 — Garbus stayed in touch with the families of the Gilgo victims. And, in 2023, their text groups lit up with a flurry of new messages: an arrest had been made at last.

“It was a different kind of feeling than the Mari text, but I just thought I had to bring this full circle,” Garbus says. “There were so many questions left unanswered. I felt so invested in this case.”

The suspect was Rex Heuermann, an architect who worked in Manhattan (where most of his alleged victims worked as escorts) and lived on Long Island. His towering physical description and even that of his unique car had been given to police years earlier, but were never investigated until a task force was formed in 2023 by new leadership in the Suffolk County Police Department to reexamine the case. It took the task force less than six weeks to find Heuermann, something the previous investigation hadn’t done in 12 years.

While “Lost Girls” had focused primarily on Mari’s search for Shannan, Garbus felt a responsibility to tell the story of all the victims, the loved ones they left behind — and the grossly mishandled investigation. It wasn’t mere police bungling — there was corruption at the highest levels of local law enforcement, which was eventually exposed. “I was watching the arrest of Jimmy Burke, the police chief of Suffolk County, just seeing all the different shifts and changes in the case like it was almost Shakespearean,” Garbus says. So she brought her renewed commitment to Netflix in the form of the docuseries “Gone Girls: The Long Island Serial Killer,” all three episodes of which are now streaming.

The series begins with the events of Shannan’s final night, as it led directly to the gruesome discoveries, but Garbus then shifts the focus to the support network formed by the mothers, sisters, daughters and friends of the other victims who advocated for justice  when most of the press and the police tacitly dismissed these women’s deaths because of their professions. “They became really skillful media activists for their daughters and mothers,” she says of the women.

In talking about that network of support, she points to a dinner shared by those women at the end of Episode 3, when Missy, Brainard-Barnes’ sister, tells Liliana, Waterman’s daughter, “You look like her.”

“It’s as if Missy had known Megan, but she never met her,” Garbus says. “That is something you say when you know someone. But that’s how tight these women and this family are, and no one bats an eyelash at it. I’m sure they weren’t thinking that they were saying anything remarkable in that moment, but it is remarkable.”

Garbus calls the making of “Gone Girls” a “fascinating journey for me,” because it put her in these vulnerable spaces with the families, with whom she had to build relationships. “So much true crime out there is focused on the perpetrator, and so I think there is some weariness about being involved in something that might be about him or his wife, or participating in a show that sensationalizes these crimes. We had to have a lot of conversations, and trust does get built.”

Part of the journey for Garbus was also talking to people she’d never met during “Lost Girls,” specifically Sarah Karnes, a friend of Brainard-Barnes’ who had worked with her as an escort. In the documentary, Karnes details the elaborate safety nets they would put in place when they met with clients, including codewords, text messages and even banging on the door after an hour threatening that their boyfriends were coming home to scare off aggressive men. That education, Garbus says, helped her understand the resiliency of these women, and how survivors’ guilt is a real thing.

“They had all these different ways of intimidating anybody who might be getting out of control, and the fact that Sarah just happened to go home that night is something that is still so raw and it eats at her, and it’s been 15 years,” Garbus says. “It’s the ripple effect of these crimes that you see. It is not just the victim’s life that is destroyed, it is so many others.”

She silos Heuermann’s inclusion in the series to the final episode, giving the victims’ stories much more time to live and breathe. This deliberate strategy is something she learned while adapting Michelle McNamara’s book, “I’ll Be Gone in the Dark,” about the Golden State Killer for HBO a few years ago. She recalls something McNamara wrote about how serial killers are the least interesting parts of these stories. “They are just damaged,” Garbus says. “At the end of the day, the stories of those they harmed, those who loved them and what it takes to get justice are ultimately more sticky and more interesting and more human. So I’m in the Michelle McNamara school on that.”

But Garbus admits she was shocked at Heuermann’s connections to her team’s network of contacts in New York. In a wild twist, Garbus says Amy Ryan, who played Mari in “Lost Girls,” actually knew Heuermann and recognized him after his arrest.

“He was an architect working on her building,” Garbus says. “She just called me that morning and said, ‘Liz, he was in my house.’ She had been on emails with him.”

She adds: “As it turns out, we know tons of people for whom that was the case, because in that area of Brooklyn, he worked on a lot of those buildings. He was really well known to get permits through the system. But he also had a mixed reputation. We heard he was difficult to deal with and he would overbill. Anecdotes started pouring out from our Brooklyn contacts, and, in any case, there he was all along.”

One thing audiences won’t see in the final episode of “Gone Girls” or “Lost Girls” is a detailed account of Mari’s death. According to court documents, her daughter Sarra, who suffered from schizophrenia, stabbed her mother 227 times and ultimately bludgeoned her with a fire extinguisher. Sarra was convicted of second-degree murder and sentenced to 25 years to life. But Garbus was clear that crime was not part of the Gilgo story in “Gone Girls” because Shannan is still not considered a victim of the serial killings with which Heuermann is charged. Despite Mari’s adamant belief that it is too big of a coincidence for Shannan to have died so close to other victims that share her similar profile, law enforcement still maintains her death had a different MO. As such, Mari’s murder is only briefly mentioned in the series, along with Waterman’s late mother, Lorraine Ela.

“‘Gone Girls’ is really focused on the case built against Rex Heuermann and, as you know, Shannan is not a part of that case, so really it wasn’t appropriate,” she says. “In “Lost Girls,” I think we had a narrative about the most powerful and transformative event of Mari’s life… What happened between Mari and Sarra felt like a different story, and an incredibly complicated one.”

At a moment when sensationalized true-crime documentaries are often the ones that top the trending charts, Garbus knowing where to draw the line is what sets quality apart from quantity in the streaming age. With her husband Dan Cogan, Garbus co-founded Story Syndicate in 2019 as a place to produce top-tier documentaries for an industry hungrier than ever for stories. Having helped kick off Netflix’s age of documentaries with her Oscar-nominated  “What Happened, Miss Simone?” in 2015, Garbus is an expert in an increasingly unpredictable field.

“When I started in this business, there was no promise of a streamer revolution,” she says. “But then, it happened and there was an explosion in distribution avenues. There was actually a real appetite for quality films and filmmaking. ‘What Happened, Miss Simone?’ was the first documentary that Netflix ever commissioned, so that was a real maker of a moment of change. It was a moment when you could do this as a full-time job.”

But in the interim, the insatiable need for more documentaries, specifically in the true crime genre, has led to an oversaturation with multiple streamers producing competing series on the same subject, diluting the impact of them; and other shoddier documentaries made on the fly to stay timely with news cycles. Meanwhile, Story Syndicate has continued to focus on the few over the many, finding homes for its more refined recent projects like “Last Call: When A Serial Killer Stalked Queer New York” (HBO), “Stolen Youth: Inside the Sarah Lawrence Cult” (Hulu), “Number One on the Call Sheet” (Apple TV+) and “Sally” (National Geographic).

“There’s been a contraction in our industry, and all over,” she says. “There’s been a race to safety for people, away from things that are experimental or less commercial. Every once in a while, something extraordinary pops through. But tastes are much more conservative and that’s not as much fun. Some of the projects I used to be able to get made very easily are bigger uphill battles now. But again, these things are cyclical, and from where we were when I started, there are a lot more avenues for people seeing documentaries than there were then.”

With the future prospects of the documentary business uncertain, would Garbus ever consider returning to the story of “Gone Girls” should Netflix come calling? Heuermann’s trial, a date for which has not yet been set, will likely answer that question.

“If there is a lot that we learn in the trial that puts pieces together we haven’t been able to put together, then yeah, I think it might be worth taking another look at,” she says. “If it is just awfulness, then no. But if there is something we can take away from it that is socially useful, then maybe yes.”

Follow up or not, Garbus plans to remain a resource for the families in any way she can, especially during the eventual trial. “I hope to be able to attend the trial, and be a shoulder to lean on for the families or a person to help, if I can, interpret their points of view on it for the press,” she says. “This is going to be something that I am sticking with, and yeah, these folks mean a lot to me, and their trust is not something I take for granted.”