Who Was The Long Island Serial Killer That Terrorized New York For Nearly 30 Years?

Published March 10, 2024
Updated March 27, 2024

Beginning in the 1990s, the Long Island Serial Killer was suspected of murdering between 10 and 16 people and discarding them near Gilgo Beach in New York.

Long Island Serial Killer

Suffolk County Police DepartmentThe first four victims of the Gilgo Beach Murders identified in the Long Island Serial Killer case. Counter-clockwise from left: Amber Lynn Costello, Maureen Brainard-Barnes, Megan Waterman, and Melissa Barthelemy.

From 1996 to 2011, scores of women disappeared near the beaches of Long Island in New York. Many of them were sex workers who had advertised their services on Craigslist, but it wasn’t until 2010 that police realized that a number of the missing women might’ve been kidnapped and killed by a single murderer — now dubbed the Long Island Serial Killer.

The hunt for the mysterious killer only began after the disappearance of Shannan Gilbert, a Craigslist sex worker who had called 911 in a panic in May 2010 while at a client’s home in Oak Beach, saying, “There’s someone after me.” Multiple witnesses claimed that she had run off on her own, with no one chasing after her, but authorities remained suspicious.

Officer John Mallia of the Suffolk County Police Department began searching for the missing Gilbert shortly thereafter, but it wasn’t until December of that year that he and his police dog happened upon something incredibly disturbing: the bodies of four murdered women near Gilgo Beach.

Dubbed the “Gilgo Four,” none of these victims turned out to be Gilbert. But the women — Amber Lynn Costello, Maureen Brainard-Barnes, Megan Waterman, and Melissa Barthelemy — were all escorts who advertised on Craigslist just like her. Before long, investigators had located the remains of up to 16 victims in the region. Now, authorities believe that at least four and as many as 11 of those people may have been killed by the same murderer.

For years, the case of the Gilgo Beach Murders remained unsolved, and police struggled to name a single suspect. Because of this, investigators thought the Long Island Serial Killer might be someone with intimate knowledge of law enforcement. But then, in July 2023, police arrested a man that few would’ve suspected: an architect named Rex Heuermann.

How Police First Discovered The Long Island Serial Killer’s Victims

Dominick Varrone

Suffolk County Police DepartmentSuffolk County Chief of Detectives Dominick Varrone told the public about the Gilgo Four after they were discovered.

Long Island’s South Shore is typically seen as a dreamy paradise on the East Coast with shimmering water, plenty to do in the summer, and a tight-knit community that many call home. But for 24-year-old Shannan Gilbert and several other young women, it became a place of nightmares.

Though Gilbert’s body wouldn’t be found until December 2011 — about a year after the discovery of the Gilgo Four — her 911 call was key to authorities finding out that something was terribly amiss on Long Island.

Officer John Mallia of the Suffolk County Police Department was assigned to look for Gilbert about a month after she disappeared in Oak Beach in May 2010. He and his police dog, a German Shepherd named Blue, searched in Oak Beach and other nearby communities for several months.

On December 11, 2010, Blue picked up an unusual scent, according to The New York Times, which led Mallia to the first victim’s skeletal remains. “The tail starts wagging; he’s making adjustments with his head,” Mallia recalled. “There was some burlap, and most of the skeleton was there.”

Gilgo Beach Murders

Thomas A. Ferrara/Newsday RM via Getty ImagesAn evidence marker along Ocean Parkway near Gilgo Beach, New York, in 2011.

Just two days after finding the first victim’s remains, Mallia discovered a second body wrapped in burlap — approximately 500 feet away from where the first body had been found. Later that day, he and Blue uncovered two other bodies nearby, which were also wrapped in burlap.

After authorities uncovered the first victims of the Gilgo Beach Murders, they knew they had to alert the public. According to LongIsland.com, Suffolk County Police Commissioner Richard Dormer made the bleak announcement: “Four bodies found in the same location pretty much speaks for itself. It’s more than a coincidence. We could have a serial killer.”

Meanwhile, Suffolk County Chief of Detectives Dominick Varrone pointed out the eerie similarities between the murdered women: “Very petite. 5 foot or under, 100 pounds,” Varrone said. The women were all in their 20s and they were all sex workers who had found their clients through Craigslist. And it was later revealed that they had all been strangled to death.

They were 22-year-old Megan Waterman, 25-year-old Maureen Brainard-Barnes, 24-year-old Melissa Barthelemy, and 27-year-old Amber Lynn Costello. And before long, police began to believe there were more victims.

The Investigation Of The Gilgo Beach Murders

Map Of The Long Island Serial Killer's Victims

Suffolk County Police DepartmentA map of the locations of the Gilgo Four and other potential victims of the Long Island Serial Killer.

A few months into the Long Island Serial Killer case, police widened their search area. By April 2011, they’d uncovered partial remains of three other dead women, now known to be Jessica Taylor, Valerie Mack, and Karen Vergata. Previously, other remains of Vergata had been found on Fire Island in 1996, other remains of Mack had been located in Manorville in 2000, and other remains of Taylor had been uncovered in Manorville in 2003.

Though the condition that these women were found in differed from the Gilgo Four — as they were not hidden by burlap and had clearly been dismembered — it was eventually learned that these three victims had also worked as escorts and they were close in age to the original four victims.

According to NBC New York, authorities also found the partial remains of a still-unidentified woman whom they nicknamed “Peaches” due to a tattoo she had on her body. Previously, Peaches’ other remains had been found in West Hempstead in 1997. They also located the remains of a still-unidentified toddler, who was revealed to be Peaches’ daughter by DNA testing. And they found the remains of yet another still-unidentified victim who was either a man dressed in women’s clothing or a transgender woman.

Long Island Serial Killer's Potential Victims

APThree women connected with the Gilgo Beach Murders case who may have been victims of the Long Island Serial Killer. From left to right: Jessica Taylor, Valerie Mack, and Shannan Gilbert.

This brought the total number of victims found in or near Gilgo Beach to 10, until Shannan Gilbert’s body was finally located near Oak Beach in December 2011. Though police believed she may have accidentally drowned, her family members still thought she had been murdered — and an expert hired by the family declared that it may have indeed been a homicide.

Disturbingly, police also uncovered a number of body parts that were never linked to any known victims, including human teeth.

Unsurprisingly, identifying the victims of the Gilgo Beach Murders was challenging for investigators. It took years of DNA analysis, research, and examining evidence to figure out which body parts belonged to which people, and the identities of some of the victims still remain a mystery.

Though police offered a reward of $25,000 for any information that led to an arrest of the murderer now known as the Long Island Serial Killer, few valuable leads emerged. And before long, the case went cold.

Newly Publicized Evidence In The Long Island Serial Killer Case

Memorial To Victims Of The Gilgo Beach Murders

Thomas A. Ferrara/Newsday RM via Getty ImagesA makeshift memorial for a victim in the Gilgo Beach Murders.

For nearly a decade, there were few updates in the Long Island Serial Killer case. Eventually, authorities revealed the names of victims they were previously unable to identify, like Taylor, Mack, and Vergata, but they still struggled to locate a suspect who might’ve killed them and the others.

Some believe that lack of transparency from authorities was a big factor in why the case remained cold for so long. For instance, much more was known about the Long Island Serial Killer’s victims than what was publicly released at first. But in 2022, the new Suffolk County Police Commissioner Rodney Harrison sought to change that by releasing further information.

He said, “As the Homicide Squad continues its tireless work on this investigation, we believe now is the right time to disseminate this previously unreleased information in hopes of eliciting tips from the public and providing greater transparency about the victims.”

Harrison compiled as much information about the Gilgo Four as was known — including where they lived, where they worked, their aliases, any tattoos they had, and when they were last seen alive — and released all of it to the public to look over with fresh eyes. He also increased the reward to $50,000 for any information that led to the arrest of the serial killer.

The police also released the audio from Shannan Gilbert’s 911 call from the night she vanished. In the tape, she tells the operator, “There’s somebody after me.” According to CBS News, Gilbert’s family says the tape proves that Gilbert’s death was no accident, despite what the police said.

Gilbert’s sister Sherre said, “It doesn’t matter if people believe she’s a victim of the Long Island Serial Killer or not. Something happened to her that night.”

Meanwhile, Harrison instructed a new task force to focus on the Gilgo Beach Murders and track down the Long Island Serial Killer. Amazingly, in a matter of weeks, they were able to identify a suspect: Rex Heuermann.

How Rex Heuermann Became The Prime Suspect In The Gilgo Beach Murders

Rex Heuermann The Suspect In The Gilgo Beach Murders

ZUMA Press, Inc./Alamy Stock PhotoRex Heuermann, the New York architect identified as the prime suspect in the Gilgo Beach Murders.

New York architect Rex Heuermann was first identified as a suspect in March 2022, thanks to information in the original case files. As it turned out, victim Amber Lynn Costello’s roommate had provided information about one of her clients and the vehicle he drove. Investigators looked into the vehicle, a first-generation Chevrolet Avalanche, and the tip from the roommate that this same client was calling her “incessantly” before her disappearance.

Since Costello — and the other women of the Gilgo Four — had all been in contact with a client who used a burner phone, police enlisted the FBI’s help to figure out where the calls were coming from. As it turned out, most of them connected to cell towers in a small region in Massapequa Park on Long Island. With this new information, plus the existing evidence about the vehicle, Rex Heuermann emerged as a suspect, since he lived in Massapequa Park and drove a vehicle with that make and model during the murders.

According to CBS News, authorities soon began to tail Heuermann, and tested his DNA after he threw out a pizza box with the crust still inside. As it turned out, the DNA on the crust was found to be consistent with the DNA in a male hair that was found near victim Megan Waterman.

Meanwhile, Rex Heuermann was also linked to burner phones used to arrange meetings with Waterman and other women of the Gilgo Four. And an investigation of his search history proved equally troubling, as he had frequently searched for torture pornography, the use of cell phone tracking to solve crimes, and updates on the Long Island Serial Killer case.

At some point during the investigation, Heuermann began fearing that police were onto him, as he obtained data wiping software to try and destroy potential evidence on his electronic devices. But he didn’t go into hiding.

Rex Heuermann The Accused Long Island Serial Killer

James Carbone/New York Daily News/TNS/Tribune Content Agency LLC/Alamy Stock PhotoRex Heuermann appearing at Suffolk County Court in Riverhead, New York, on September 27, 2023.

In July 2023, police arrested 59-year-old Rex Heuermann in connection with the Gilgo Beach Murders. According to the Associated Press, he was initially charged with killing three women of the Gilgo Four: Melissa Barthelemy, Megan Waterman, and Amber Costello. But by January 2024, police had gathered enough evidence to charge him with the killing of the fourth woman of the Gilgo Four, Maureen Brainard-Barnes. Only time will tell if he’ll be charged with any other deaths linked to the case, as police say the other victims could’ve potentially been murdered by another killer or killers.

His arrest shocked many in Massapequa Park who knew him as a “well-dressed” family man devoted to his wife and children. (His wife, who was said to be “blindsided” by the charges, filed for divorce shortly after his arrest.) One former neighbor said that if he is found guilty, “He was living a double life… You know, the regular guy who goes to work, has kids in the local school and in a good neighborhood, but he’s killing people on the side.”

Equally shocked were many of his colleagues and clients, who simply saw him as a hard-working architect devoted to detail at his Manhattan firm. One property manager who worked with him for about three decades described him as “a gem to deal with, highly knowledgeable” and “a big goofy guy.”

But according to The New York Times, some weren’t nearly as surprised. One of his neighbors said, “He was somebody you don’t want to approach.” One former president of a building’s board that hired Heuermann to oversee renovations called him “a really kind of cold and distant person, kind of creepy… There was a swagger — ‘I’m the expert, you’re lucky to have me.'”

Rex Heuermann, for his part, has maintained his innocence in the case so far and has insisted that he was not responsible for the Gilgo Beach Murders. While Heuermann has not been put on trial yet and therefore has not been officially found guilty of the crimes, it seems as though the long mystery of the Long Island Serial Killer may finally be coming to a close.

After reading the chilling story of the Long Island Serial Killer and why Rex Heuermann may be responsible, learn about the most bizarre cases that Unsolved Mysteries helped solve. Then, read the disturbing story of the Chicago Strangler, who may have murdered up to 50 women.

Jessica OConnor
Jessica O'Connor is a public historian focusing on Deep South Black History with degrees from Winston-Salem State University and the University of North Carolina at Greensboro.
Jaclyn Anglis
Jaclyn is the senior managing editor at All That's Interesting. She holds a Master's degree in journalism from the City University of New York and a Bachelor's degree in English writing and history (double major) from DePauw University. She is interested in American history, true crime, modern history, pop culture, and science.