Rex Heuermann, an architect accused of murdering several women near Gilgo Beach on Long Island, is awaiting trial, and a new documentary about the case is set to premiere on Netflix on March 31.

The three-part series, Gone Girls: The Long Island Serial Killer, directed by Liz Garbus, includes interviews with friends and family of the victims, as well as law enforcement officials who have been investigating the case since Shannan Gilbert, a sex worker, disappeared in 2010.

Garbus previously interviewed some of the victims’ relatives for Lost Girls, a 2020 film inspired by the case, starring Amy Ryan and Lola Kirke, and based on Robert Kolker’s book Lost Girls: The Unsolved American Mystery of the Gilgo Beach Serial Killer Murders.

“We were hoping it would put more public pressure on getting justice for these families,” Garbus told TIME.

After Heuermann’s arrest in 2023, where he was charged with the murders of seven women, she reconnected with some of the families and began working on a documentary.

Here’s how Gone Girls details the key events that led to the 2023 arrest.

How the suspected Gilgo Beach serial killer got arrested

In 2021, when Suffolk County appointed Rodney Harrison as the new police commissioner, he established the Gilgo Beach Homicide Investigation Task Force in 2022. This task force comprised federal, New York state, and local law enforcement officers who worked on digitizing the evidence to facilitate easier searches.

Authorities were searching for someone over six-foot-four-inches tall who drove a Chevy Avalanche. They knew the missing women had received calls from a burner phone and determined that the phone belonged to someone who commuted between Massapequa Park on Long Island and New York City.

The task force’s first meeting occurred on February 1, 2022, and about six weeks later, on March 14, 2022, they began tracking Heuermann, a married father of two who worked at an architecture firm in Manhattan. They noticed the burner phone’s presence wherever Heuermann went. Authorities observed him adding minutes to the burner phone and discovered anonymous email accounts used to contact sex workers. To obtain a DNA sample, they retrieved a pizza box he discarded and took the leftover crust. The DNA matched hairs found at a crime scene.

In Gone Girls, a former employee of Heuermann’s mentioned his extensive knowledge of Long Island beach areas. Police found hundreds of firearms in his basement and seized his computer to analyze his Internet searches, which frequently involved the Gilgo Beach murder investigation, the victims, and pornography depicting the abuse of women.

Crucially, police recovered a deleted document from a hard drive in Heuermann’s house detailing best practices for torturing victims, lists of required equipment, and methods for disposing of evidence.

Heuermann has pleaded not guilty to all seven murder charges.

The primary mystery remains the motive behind the murders. Garbus stated that she did not come to a firm conclusion regarding what drove the alleged murderer Heuermann to target sex workers, but noted, “He went on dates with people who were working as escorts, and they were suspicious of him, but those women wouldn’t go to the cops because they didn’t want to be arrested.”

Amanda Funderburg, the sister of victim Melissa Barthelemy, described Heuermann as a “monster.” When asked what she would say to Heuermann if she had the chance, she responded, “He’s not as smart as he thought he was.”

Other family members of the victims are cautiously hopeful about the case’s outcome. “When someone is found guilty, that’s when it will be like…we found Megan’s killer,” said Elizabeth Meserve, aunt of Megan Waterman, one of the women Heuermann is charged with killing. “But I think nobody wants to get too hopeful, to be disappointed.”

Why it took so long to solve the murders

While Gone Girls examines the local politics that hampered the case, Garbus also points to a wider societal stigma against sex workers.

“When you start to learn about these families who lost their loved ones, hopefully it makes you question that as you look at these stories in the future,” Garbus said.

She hopes the film fosters greater empathy not only for the missing but also for all crime victims marginalized by society due to race and class.

As she explains, “I think what documentary and filmmaking in general does is it allows you to walk in other people’s shoes. It brings you as close to them as you might ever get in your life. The more that we walk in other people’s shoes, the more we can have empathy for them and be connected in a society.”