Is Netflix’s ‘Lost Girls’ a True Story? Director Liz Garbus Explains

Warning: This article contains spoilers for Lost Girls on Netflix.

Every film that four-time Oscar-nominated filmmaker Liz Garbus has directed has been based on a true story, from The Farm: Angola, USA in 1998 to What Happened, Miss Simone in 2016. But those were documentaries. Lost Girls, on Netflix today, is based on a true story—or, as the official promos say, “based on true events”—but it’s also Garbus’s first-ever narrative feature.

“There have been great docs on these murders,” Garbus told Decider, referring to the killings of nearly a dozen sex workers in Long Island, whose bodies were discovered in 2010 and 2011. “But you couldn’t tell this story in the same way through a documentary, because these scenes had already been lived.”

Lost Girls was written by Michael Werwie—who wrote another serial killer feature for Netflix last year, Extremely Wicked, Shockingly Evil and Vile—and is based on Robert Kolker’s best-selling 2011 non-fiction book of the same name. But while Kolker interviewed family members of five sex workers who were killed, the film version of Lost Girls focuses mainly on one: Mari Gilbert, played by Amy Ryan (Gone Baby Gone, The Office).

What is the Lost Girls true story? Who is Mari Gilbert?

Mari’s 24-year-old daughter Shannan Gilbert first went missing in May 2010. It was her disappearance—and Mari’s insistence that the police search where she was last seen near Ocean Parkway, Long Island—that led authorities to eventually discover ten bodies, most of whom were sex workers like Shannan. Their deaths are believed to be the work of an unidentified serial killer in Long Island over a period of 20 years, referred to as the Long Island serial killer, or LISK.

Shannan’s body wasn’t found until over a year later, and the identity of the Long Island serial killer was never found. Why? According to Gilbert—who loudly said as much to any media organization who would listen—the police weren’t taking the case, and the lives of these girls, seriously.

“The character of Mari Gilbert was one that I really understood and empathized with,” Garbus said in a phone interview with Decider. “This is a story about believing women, and having women’s voices be taken seriously within our institutions.”

When it came to adapting Gilbert’s real life for the screen, Garbus found that the process wasn’t so different from her award-winning documentary work. “With documentaries, people say, ‘This is real,'” the director noted. “But you skip over things, you ally things, you decide what you include, what you don’t include, and which way you shoot it. All of that affects a ‘reality.’ The same is true here. When you’re making a 100-minute film, you compress things. But you have a north star which is your understanding of the characters of the story, and you use that north star to guide you through those decisions.”

What changes were made to the Lost Girls true story? What stayed the same?

The biggest detail that was changed, said Garbus, was the Gilbert family themselves. In real life, Mari Gilbert had four children, not three. But one of Gilbert’s daughters, Stevie, does not exist in the film.  “Stevie, another daughter of Mari’s, had not been depicted in Bob’s book as an active participant in Mari’s search for Shannan,” Garbus explained. “Whether or not that actually happened, well, we were working from Bob’s book.”

While some of the actors, such as Ryan, closely resemble their real-life counterparts, others, like Gone Girl‘s Lola Kirke who played a victim named Kim Overstreet, not so much. “I wanted the actors to feel free to bring their and our interpretations,” Garbus said. “And even though Lola looks very different from Kim, when she spoke to her real family, they said, ‘You nailed Kim!’ I think she captured the spirit.”

Smaller details were changed, too, like the song a young Shannan Gilbert sings on a home video watched by her mom. “Beautiful Dreamer” by Stephen Foster, was chosen by Garbus and her team, but was based on the fact that “Shannan loved to sing and perform and dance,” the director said. “That was one of her passions, when she was in elementary school, so that aspect was authentic, but whether or not she actually performed that song, that was something that we added.” (The song was originally a number from Annie, based on a detail from Kolker’s book that Shannan had auditioned for her school’s production of the show, but Garbus couldn’t get the rights.)

On the other hand, when it came to where Lost Girls was filmed, Garbus wanted to be as authentic as possible, including on Ocean Parkway near Jones Beach and Gilgo Beach, where many of the bodies were found. “It’s a desolate dumping ground, and there is a sadness to it. It was important to understand how close to New York you can have this desolate landscape.”

The crew wasn’t able to shoot at Oak Beach, where Shannan’s body was found, because the residents denied Garbus permission to film there, but Garbus found a similar community on the North Fork of Long Island. And she did manage to shoot in Ellenville, where Mari Gilbert raised her children. “It was important to depict that Upstate New York is a depressed community,” Garbus said. “Mari is a woman who is holding two jobs without a partner, trying to raise her children.”

What happened to the real Mari Gilbert?

The most shocking revelation of Lost Girls comes at the very end, via an end-credit note: Mari Gilbert died on July 23, 2016. She was stabbed to death by her own daughter, Sarra, who is played by Oona Laurence in the film. Sarra, who was 27, was said to have schizophrenia, was charged with second-degree murder, and sentenced to 25 years to life in prison.

Mari Gilbert’s death was a shock to Garbus, who first signed onto the Lost Girls project in 2015 and had just spoken to Gilbert a few months prior, to discuss the film. “It was just the strangest, craziest text to receive. It didn’t make any sense,” Garbus said in an interview transcribed in the Lost Girls press notes. The director added to Decider that, “[her death] made the film feel even more urgent, as if it wasn’t already.”

Gilbert, Garbus said, was thrilled about the film, and eager to get it off the ground. “She understood—as we portray in the film—the power of media and making change,” Garbus said, adding that Gilbert also had a few requests for the director—including to never show her character smoking while giving a press conference because while she did smoke, she would never smoke on TV.

“I thought that was a great detail,” Garbus said, “because what it said was, ‘I know the role they want me to play to be taken seriously. That’s bullshit, but I know what it is and I’m gonna do it, I’m gonna play their game.’ So off of that, we created this scene of Mari buying the suit in the film, trying to put on the codes of respectability that she shouldn’t have to put on.”

Gilbert’s death is not a plot point in the film, but a subplot about mental health is woven throughout. We learn that Shannan grew up in foster care because Mari felt she couldn’t provide the mental healthcare she needed, and Mari often nags Sarra about taking her mood stabilizer pills. “I know from people who were close to Mari that she really was kind of relishing that role, of Sarra’s mental health care,” Garbus said. “So the fact that she was finally able to do that in a way that she wasn’t able to do for Shannan, and to have it end this way… it’s just so tragic.”

The silver lining is the renewed attention on the Long Island serial killer, thanks to Lost Girls, which Garbus hopes might lead to finally solving the case that Mari Gilbert worked so hard to get the world to pay attention to. Indeed, there has already been some movement: The Suffolk County Police Department held its first press conference in years on the case to reveal new evidence. 

“If Mari taught us one thing,” Garbus said, “it was that public conversation and pressure has created the need for police action. Following in those footsteps, I do hope that the continued attention to this case through this film will continue to make the police aware that people want justice.”

Watch Lost Girls on Netflix