A man has been charged with multiple counts of murder in connection with the unsolved killings of women whose bodies were found on Long Island's Gilgo Beach more than a decade ago, according to court documents released Friday. The suspect was identified as Rex Heuermann, of Massapequa, Long Island.

The documents show that Heuermann, 59,  has been charged with three counts of first degree murder and three counts of second degree murder in the deaths of Melissa Barthelemy, Megan Waterman and Amber Costello. Those three women, along with Maureen Brainard-Barnes, were all found in close proximity to one another in 2010 and have been called the "Gilgo Beach Four." The court filing says Heuermann is considered "the prime suspect" in Brainard-Barnes' death as well.

In all, the bodies of at least 10 victims were found in the area in 2010, believed to be the victims of a serial killer.

"Members assigned to the Gilgo Beach Task Force, which consisted of numerous detectives and investigators from the Suffolk County Police Department, as well as our partners in the FBI, did place one individual under arrest," Suffolk County Police Commissioner Rodney Harrison said Friday.

Heuermann was taken into custody late Thursday night and was arraigned Friday in Suffolk County court in Riverhead. 

He pleaded not guilty, and the judge ordered him held without bail.

Suffolk County District Attorney Raymond Tierney revealed new details about the investigation in a news conference Friday afternoon, saying it involved more than 300 search warrants. 

"This case is not over; it's only beginning," Tierney said. "We're continuing to execute search warrants and anticipate getting more evidence."

According to court documents filed in the case, investigators began a "comprehensive review of every item of evidence" in the case in 2022, which led them to take a closer look at a Chevrolet Avalanche registered to Heuermann at the time of the murders, similar to one reported seen by a witness. The investigation also turned up connections with burner cellphones and other phone data allegedly linked to the suspect. 

Tierney said FBI analysts were able to compare the cell site data of the victims' cellphones and data from seven prepaid, anonymous burner phones the suspect used to communicate with each of the victims, which gave investigators a lead. 

In addition, the court filing says a hair found on burlap that wrapped one of the victims was determined to be a DNA match to Heuermann, based on a DNA sample retrieved from crusts in a pizza box he discarded.

Tierney said the burlap found wrapped around the three victims, who were each bound in the same way, was camouflage burlap, typically used in duck blinds.

Authorities recovered hairs found with each of the victims, which were too degraded to test for DNA with the techniques available at that time. But the technology improved, Tierney said, and investigators were able to test the hairs with more advanced methods using mitochondrial DNA.

Tierney said investigators had to balance continuing to gather evidence with public safety.

"The initial plan was to allow the grand jury investigation to go a little further, but at a certain time, again, the task force felt for reasons having nothing to do with the evidence in the case, we had to take him down," he said.

Tierney also said investigators gathered evidence of the suspect's internet search history, which included what he described as "torture porn" — "depictions of women being abused, being raped and being killed" — as well as photos of the victims, photos and locations of the victims' relatives, and over 200 searches for information about the investigation itself.

The court documents note that while the defendant is "not yet charged" in connection with the murder of Maureen Brainard-Barnes, "Rex A. Heuermann is the prime suspect in her death," and the investigation is continuing. 

"Moreover, there is substantial evidence of Defendant Heuermann's involvement in the disappearance and death of Ms. Brainard-Barnes, which evidence closely fits the modus operandi of the Defendant in relation to the deaths of the other three women," the filing states.

The major development comes more than a decade after the victims' bodies were found on Gilgo Beach. The long-unsolved killings were the subject of numerous CBS "48 Hours" reports and the 2020 Netflix film "Lost Girls."

The victims were found across a stretch of Ocean Parkway on Long Island in late 2010; several of the women were identified as sex workers. The case has long baffled investigators and no arrests had ever been made.

Residents of Massapequa Park told CBS New York they were stunned by the news on Friday.

"We've been here for about 30 years, and the guy's been quiet, never really bothers anybody," next-door neighbor Etienne DeVilliers told the station. "We were kind of shocked, to tell you the truth." 

DeVilliers said Heuermann is married, with two children. He added that his neighbor told him he was an architect.

"Like I said, we're shocked. Because this is a very, very quiet neighborhood. Everybody knows each other, all of our neighbors, we're all friendly. It's never been a problem at all," DeVilliers said.

Actor Billy Baldwin tweeted on Friday that he went to high school with Heuermann.

"Woke up this morning to learn that the Gilgo Beach serial killer suspect was my high school classmate Rex Heuermann," Baldwin tweeted, saying they went to Massapequa's Berner High School and graduated in 1981.  

On Friday, officers converged on a small red house that had been raided earlier in the morning in Massapequa , the Associated Press reported. Investigators were seen outside the home, which appeared to be in disrepair.

"This house sticks out like a sore thumb. There were overgrown shrubs, there was always wood in front of the house," neighbor Gabriella Libardi told the AP. "It was very creepy. I wouldn't send my child there."

Barry Auslander, another neighbor, told the AP the man who lived in the house commuted by train to New York City each morning, wearing a suit and tie.

"It was weird. He looked like a businessman," said Auslander. "But his house is a dump."

• What we know about Rex Heuermann, suspect in Gilgo Beach murders

The apparent breakthrough in the hunt for a suspect in what's become known as "the Long Island serial killer" case came a little more than a year after police released audio of a 911 call made by Shannan Gilbert just before she vanished in 2010.

Investigators were searching for Gilbert when they found other remains on Gilgo Beach in December that year — women in their 20s whose remains had been wrapped in burlap sacks. Known as the Gilgo Four, they were later identified as Maureen Brainard-Barnes, abducted in 2007; Melissa Barthelemy in 2009; and Megan Waterman and Amber Costello, who went missing in 2010. Six more sets of remains were found along Ocean Parkway the following spring. 

The Suffolk County Police Department released the full audio of Gilbert's 911 call last year, as well as maps and other images showing what authorities believe happened on May 1, 2010, the night she disappeared.

The police said in 2022, however, that "based on the evidence, the facts, and the totality of the circumstances, the prevailing opinion of Shannan's death, while tragic, was not murder and most likely not criminal."

Investigators voiced hope then that releasing the 911 audio would lead to answers in the larger search for the Gilgo Beach killer, and officials announced a doubling of the reward for information on the murders to $50,000.

"We are making real progress," Suffolk County Police Commissioner Rodney Harrison said in May 2022. He said he hoped new information released to the public would bring new leads on the notorious crime spree that had stumped police for a dozen years.

CBS News senior investigative producer Pat Milton contributed to this report.

In:
• Serial Killer
• Murder
• Gilgo Beach
• Long Island
• New York

Tucker Reals

Tucker Reals is the CBSNews.com foreign editor, based at the CBS News London bureau.