By Emma Tucker and Eric Levenson

(CNN) — For more than a decade, a string of unsolved killings on Long Island, New York, known as the Gilgo Beach murders confounded investigators.

The case began in earnest with the 2010 disappearance of 23-year-old Shannan Gilbert. The search for her whereabouts led to the discovery of at least 10 sets of human remains along Ocean Parkway and launched the hunt for a suspected serial killer.

But the investigation went cold for over a decade. In the meantime, the killings were the subject of a bestselling nonfiction book, a Netflix movie and true-crime documentaries.

Authorities announced a major breakthrough in the case in July 2023 when they charged New York architect Rex Heuermann with murder in the killings of three of the four women who became known as the “Gilgo Four.”

Heuermann was later charged with four more murders – including the death of the fourth Gilgo Four victim – in incidents dating as far back as 1993.

Two forensic laboratories have determined that hairs recovered on six of the seven victims are “forensically tied” to Heuermann or members of his immediate family, or others he lived with, according to a legal filing.

In all, Heuermann is accused of killing seven people: Maureen Brainard-Barnes, Melissa Barthelemy, Megan Waterman, Amber Costello, Jessica Taylor, Valerie Mack and Sandra Costilla.

He has pleaded not guilty to three counts of first-degree murder and seven counts of second-degree murder. His defense has so far focused on undermining the prosecution’s use of cutting-edge DNA technology to tie him to the killings.

Heuermann’s trial is expected to start in September and last several months.

Here’s a timeline of the Gilgo Beach killings, how the investigation unfolded and what ultimately led to Heuermann’s arrest.

Young women missing on Long Island

Over nearly two decades, a number of women in their 20s who police said worked as escorts or sex workers went missing on Long Island.

Sandra Costilla’s remains were found in the hamlet of North Sea in 1993 by two hunters in the woods, according to court documents.

Partial remains of Valerie Mack, a 24-year-old Philadelphia mother who worked as an escort, were found in a wooded area of Manorville in November 2000, with further remains discovered in 2011, according to police.

Jessica Taylor’s remains were discovered in part in Manorville in 2003, with more found along Ocean Parkway on Gilgo Beach in 2011, according to police.

Maureen Brainard-Barnes was 25 years old when she was last seen on July 9, 2007.

Melissa Barthelemy, a 24-year-old sex worker, was last seen on July 12, 2009, in the Bronx, according to Suffolk County police. On the night she was last seen, she told a friend she was meeting a man and would be back in the morning, according to the police website. She was reported missing a few days later.

After Barthelemy’s disappearance, her family received multiple taunting calls from her cell phone, according to an attorney for her mother.

“Do you think you’ll ever see her again?” the unidentified male caller asked Barthelemy’s sister on August 26, 2009. “You won’t. I killed her,” the man added.

Megan Waterman was 22 years old and working as a sex worker when she was last seen on June 6, 2010, police said.

Amber Lynn Costello was 27 years old and living on Long Island when she was last seen on September 2, 2010. She struggled with a heroin addiction and worked as an escort to help support her habit, according to Suffolk County police.

Authorities find remains of ‘Gilgo Four’

In May 2010, Gilbert went missing in the community of Oak Beach after visiting a client, and her mother began a tireless quest to pressure police to search for her and take her case seriously.

During that search, police discovered a set of female remains in bushes along an isolated strip of waterfront property in Gilgo Beach, not far down the road from where Gilbert vanished. Those remains, of Barthelemy, were discovered on December 11, 2010, according to Suffolk County officials.

Two days later, investigators discovered the remains of three additional victims – Brainard-Barnes, Costello and Waterman – strewn across a half-mile stretch in Gilgo Beach. They became known as the Gilgo Four.

The four women, whose remains were found wrapped in camouflaged burlap, worked as escorts who advertised on Craigslist and were last seen between July 2007 and September 2010, officials said.

7 more bodies found nearby

On March 29, 2011, the partial skeletal remains of another woman were found several miles east of where the bodies of the Gilgo Four were discovered. The woman was first known as Jane Doe #5 before investigators identified her as Taylor, police said.

On April 4, 2011, three more sets of remains were found on a stretch of Ocean Parkway in Suffolk County near the beach. They included a female toddler, an unidentified Asian male and an unidentified Jane Doe #6, investigators said.

One week later, two additional sets of human remains were found in Nassau County. One set of remains was identified through DNA analysis as the mother of the female toddler. The mother’s partial remains were first discovered in 1997, officials said.

The killings of the toddler and mother were later connected to another case, according to Nassau County prosecutors.

The other set of remains “genetically matched” with remains found in 1996 on Fire Island, “significantly expanding the timeline and geographic reach” of the investigation, officials said.

In December 2011, Gilbert’s body was found in the wooded marshes of Oak Beach.

Authorities later said they believed Gilbert’s death may have been accidental and not related to the Gilgo Beach slayings.

The Gilgo Beach case then went cold for over a decade.

Decade later, new task force picks up pieces

In 2015, then-Suffolk County Police Chief James Burke was arrested and accused of beating a man in custody and conspiring to block the FBI investigation into his actions, according to court records. Burke ultimately pleaded guilty to a civil rights violation and conspiracy to obstruct justice and was sentenced to 46 months in prison, the records show.

The day of the arrest, the Suffolk County Police Deputy Commissioner announced that the FBI will join the investigation into the Gilgo Beach case.

In January 2020, Suffolk County police released photos of what it said could be a significant piece of evidence: a black leather belt embossed with the letters “WH” or “HM.” The department also launched a website to collect new tips in the investigation.

“We believe the belt was handled by the suspect and did not belong to any of the victims,” then-Suffolk County Police Commissioner Geraldine Hart told reporters at the time.

On May 28, 2020, Suffolk County Police Department identified “Jane Doe #6” as Valerie Mack, who went missing two decades earlier.

In February 2022, then-Suffolk County Police Commissioner Rodney Harrison formed a multiagency task force to investigate the Gilgo Beach killings. The task force included the Suffolk County Police Department, the Suffolk County Sheriff’s Office, the New York State Police and the FBI.

On March 14, 2022, Rex Heuermann was first mentioned as a possible suspect in the Gilgo Beach killings after a New York state investigator identified him in a database, according to Suffolk County District Attorney Ray Tierney.

Investigators started surveilling him and his family and took pieces of garbage to obtain DNA samples.

As they closed in on Heuermann, investigators used cell tower records from thousands of possible individuals to narrow it down to hundreds and then to a handful of people. Next, authorities focused on residents who also matched a physical description provided by a witness who had seen the suspected killer.

Authorities zeroed in on anyone with a connection to a green pickup truck a witness had seen the suspect driving, according to two law enforcement sources with knowledge of the case. Later, authorities learned Heuermann drove a green pickup truck registered to his brother, CNN reported.

Heuermann matched a witness’s physical description, lived close to the Long Island cell site and worked near the New York City cell sites where other calls were captured.

Personal cell phone and credit card billing records revealed numerous instances where Heuermann was in the general locations as burner phones, which authorities say he had with him at the killings. He used the phones to call three of the Gilgo Four victims and also used “Brainard-Barnes and Barthelemy’s cellphones when they were used to check voicemail and make taunting phone calls after the women disappeared,” Suffolk County prosecutors allege.

Authorities said a search of Heuermann’s computer revealed he had scoured the internet at least 200 times for details about the status of the investigation, Tierney said. Heuermann was also compulsively searching for photos of the victims and their relatives, and he was trying to track down relatives, the district attorney said.

In late 2022, detectives recovered a cup believed to have been discarded by Heuermann, but they could not get a good DNA sample from it, a law enforcement source close to the investigation told CNN.

In January 2023, investigators got a complete sample of Heuermann’s DNA from leftover crust in a pizza box he threw in the trash, a law enforcement source close to the investigation told CNN.

During the initial examination of one of the victims’ skeletal remains and materials discovered in the grave, the Suffolk County Crime Laboratory recovered a male hair from the “bottom of the burlap” the killer used to wrap Waterman’s body, according to prosecutors. Analysis of the DNA found on the victim and the pizza thrown out by Heuermann showed the samples matched.

Additionally, hair believed to be from Heuermann’s wife was found on or near three of the murder victims, prosecutors allege in the bail application, citing DNA testing. The DNA came from 11 bottles inside a garbage can outside the Heuermann home, the court document says.

Rex Heuermann arrested in murders

On July 13, 2023, Heuermann, then 59, was arrested in New York City and charged with the murders of three of the Gilgo Four victims: Melissa Barthelemy, Megan Waterman and Amber Costello, according to an indictment.

He was transported back to Suffolk County Police headquarters in the hamlet of Yaphank, the police commissioner said. In court, he pleaded not guilty to the murders and was remanded without bail.

Heuermann has owned the New York City-based architecture and consulting firm RH Consultants & Associates since 1994, according to his company’s website.

The case against Heuermann came together over two years with the restart of the investigation, in which investigators used “the power of the grand jury,” including more than 300 subpoenas and search warrants, to collect evidence and tie Heuermann conclusively to the killings, Tierney said during a news conference.

4 more murder charges for other women

In January 2024, Heuermann was charged with second-degree murder in the death of Brainard-Barnes, the fourth of the Gilgo Four, according to an indictment.

Heuermann was indicted on two new murder charges in June 2024 in connection with the 2003 death of Taylor and the 1993 death of Costilla.

A hair found underneath Taylor’s remains was linked to Heuermann, according to a bail application.

“Defendant Heuermann is the individual who murdered, stripped, restrained, and transported the remains of Jessica Taylor and Sandra Costilla, as well as the Gilgo Four, until they were each discovered in 1993, 2003, 2010, and 2011,” according to the bail application.

In a June 6 court hearing, prosecutors said investigators found disturbing content on Heuermann’s devices, including a planning document outlining a strategy for future killings.

In September 2024, Tierney announced prosecutors were seeking the public’s help in identifying a separate victim found in 2011 along the same stretch of Ocean Parkway as Waterman and Taylor. The victim, referred to as “Asian Doe,” was a biological male of Asian descent, between the ages of 17 to 23, found wearing women’s clothing. Authorities said they believe the victim died in 2006 or earlier from blunt force trauma.

Tierney did not say whether the victim was connected to the investigation into Heuermann.

In December 2024, Heuermann was charged with the murder of Valerie Mack – his seventh murder charge. There were similarities between the cutting instruments used to dismember Mack and Taylor, as well as the garbage bags containing their remains, a bail application notes.

Court rulings before trial

On September 3, 2025, Suffolk County Judge Timothy Mazzei ruled that evidence derived from cutting-edge DNA technology will be admissible at Heuermann’s trial. Prosecutors say the evidence, known as whole genome sequencing, connects Heuermann to the killings.

Heuermann’s defense attorney Michael Brown had argued whole genome sequencing has not yet been widely accepted by the scientific community and therefore shouldn’t be permitted. He said he plans to argue the validity of the technology before a jury.

Later that month, Mazzei ruled that the seven murder charges will be handled in one trial rather than separated into individual cases. Heuermann’s attorneys had argued that the killings should be separated because they involved different time frames, techniques and locations, while prosecutors said they featured overlapping evidence and witnesses.

The-CNN-Wire
™ & © 2026 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.