On the Hunt for a Monster: How Police Unraveled the Long Island Serial Killer Mystery After Years of Terror

Shannan Gilbert was working as an escort on May 1, 2010, when she vanished without a trace after visiting a client in the gated community of Oak Beach on Long Island, N.Y.

Before she fled from the man’s home, she called 911 and told an operator that somebody was after her. She ran to an elderly neighbor’s home and asked for help before darting off in the early morning light.

However, when police finally showed up, Gilbert, 23, was nowhere to be found.

A search began that led to the shocking discovery of four bodies — Melissa Barthelemy, Amber Costello, Megan Waterman and Maureen Brainard-Barnes — in December 2010. All four women were in their 20s and worked as online escorts, like Gilbert. They disappeared between 2007 and 2010.

The shocking discoveries continued. Two months later, in March 2011, authorities found the remains of more bodies along the beach.

Five of the sets of remains belonged to women. The other sets included those of a toddler — found alongside her mother — and an Asian male who was wearing women’s clothing. Two sets of the remains were later linked to the dismembered torsos of 20-year-old sex worker Jessica Taylor in 2003 and Valerie Mack in 2000 found in Manorville. Authorities believed that the killer used a hand-powered saw to dismember them.

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Police also discovered the remains of 34-year-old Karen Vergata, who went missing in 1996. Some of Vergata’s remains were found on Long Island’s Fire Island on April 20, 1996. More body parts were found on Long Island’s Tobay Beach in April 2011.

Then, in Dec. 2011, the skeletal remains of Gilbert, whose disappearance sparked the search along Ocean Parkway, were found in a marsh near Oak Beach. While the details of how she vanished are murky, police believe Gilbert somehow got lost in the inhospitable marshland and died accidentally — either of exposure or accidental drowning. Her family has long suspected that she was murdered.

The decades-long search for the suspected Long Island Serial Killer is now the subject of the Netflix documentary, Gone Girls: The Long Island Serial Killer, which begins streaming on March 31. The docuseries, directed by Liz Garbus, features interviews with law enforcement officials, friends and family of the victims as well as former coworkers of alleged serial killer Rex Heuermann who was later charged with the killings. (The trailer to the series, debuted exclusively by PEOPLE, is shown below.)

Heuermann was taken into custody in July 2023, when a task force set up to find the killer arrested the now 61-year-old architect and father of two after DNA evidence allegedly linked him to the murders of Barthelemy, Costello and Waterman.

Authorities claim Heuermann committed the murders while his wife and two kids — who lived with him at his childhood home in Massapequa Park, N.Y. — were out of state. He allegedly used four separate burner phones to arrange meetings with the women and then killed them.

During their investigation, authorities discovered that Heuermann was allegedly obsessed with the police investigation and searched more than 200 times about their hunt for the unnamed killer. Some of the alleged searches included: “Why could law enforcement not trace the calls made by the Long Island serial killer” and “why hasn’t the Long Island serial killer been caught.”

Investigators also allegedly found hundreds of internet searches about raping and torturing women, child sex abuse material and violent pornography as well as searches for his victims and their families.

He was charged with second-degree murder in the death of Brainard-Barnes in January 2024 after DNA evidence linked him to the crime.  Five months later, he was charged with killing Taylor, whose remains were found along Ocean Parkway and Manorville, and Sandra Costilla.

Costilla’s remains were discovered on Nov. 20, 1993, by two people hunting in a wooded area. She was lying on her back with her arms “outstretched over her head with her uncovered legs spread apart,” according to an amended indictment. She had several “sharp force injuries” across her body.

He was charged again in December 2024 with the murder of Mack, whose remains, like those of Taylor, were found along Ocean Parkway and in Manorville. In the months leading up to Mack’s murder, Heuermann allegedly viewed pornographic images including those showing breast mutilation and bondage by rope, which “largely coincide with the injuries inflicted on Ms. Mack’s breast and how the rope ligatures were utilized on Valerie Mack,” according to the indictment against him filed in Suffolk County.

A hair from Heuermann’s then preschool daughter Victoria was also discovered in the sealed garbage bag where some of Mack’s remains were found in Manorville, per the indictment.

Heuermann is currently being held at the Suffolk County Jail.

He has pleaded not guilty.

Gone Girls: The Long Island Serial Killer, begins streaming on Netflix on March 31.