For more than a decade, a string of unsolved killings known as the Gilgo Beach murders terrorized residents and confounded authorities on Long Island's South Shore after a woman's 2010 disappearance led investigators to find at least 10 sets of human remains and launched the hunt for a possible serial killer.

Authorities announced a major breakthrough in the case on Friday, charging New York architect Rex Heuermann, 59, with murder in connection to the killings of three of the four women who became known as the "Gilgo Four."

The suspect was taken into custody Thursday night, authorities said. He has been indicted on one count of first-degree murder and one count of second-degree murder in each of the three killings -- Melissa Barthelemy in 2009, and Megan Waterman and Amber Costello in 2010, according to the Suffolk County District Attorney.

Heuermann, who told his attorney he is not the killer, is also the prime suspect in the 2007 disappearance and death of a fourth woman, Maureen Brainard-Barnes, according to a bail application from prosecutors. He has not been charged in that homicide but the investigation "is expected to be resolved soon," the document says.

Authorities said once Heuermann was identified in early 2022 as a suspect, they watched him and his family, getting DNA samples from items in their trash as they built a case.

He was remanded without bail Friday. He entered a not guilty plea through his attorney. His next court date is scheduled for August 1.

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

2010: Authorities find first remains in Gilgo Beach murders

Police discovered the first set of female remains in bushes along an isolated strip of waterfront property on Gilgo Beach while searching for another missing woman: Shannan Gilbert, a 23-year-old from Jersey City, New Jersey who hadn't been seen since May 2010.

The remains of Melissa Barthelemy, 24, were the first to be discovered in the case during the search on December 11, 2010, according to Suffolk County officials. Two days later, investigators discovered the remains of three additional victims -- Maureen Brainard-Barnes, Amber Costello and Megan Waterman -- strewn across a half-mile stretch on Gilgo Beach.

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

2011: More remains found, including a toddler and her mother

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 Jessica Taylor, another escort whose partial remains were previously discovered in Manorville in 2003, police said.

The following month, 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 a woman initially referred to as Jane Doe #6, investigators said.

One week later, two additional sets of human remains were found in Nassau County, about 40 miles east of New York City, one of which was identified as the mother of the toddler through DNA analysis. The mother's partial remains were first discovered in 1997, officials said.

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 Suffolk County's Oak Beach. That beach is about 9 miles from where the 10 other sets of human remains were found.

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

2020: Police release photos of a key clue and ID a victim

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," former Suffolk County Police Commissioner Geraldine Hart told reporters at the time.

On May 28, 2020, New York's Suffolk County Police Department identified "Jane Doe #6" as Valerie Mack, a 24-year-old Philadelphia mother who went missing two decades earlier.

The FBI helped identify Mack's remains using advanced forensic DNA technology, officials said.

Using samples from her remains, Suffolk County investigators were able to find Mack's biological relatives through genetic genealogy, which ultimately led to her adoptive family and son, Hart said to reporters at the time.

2022: Police form task force to find killer

In February 2022, Suffolk County Police Commissioner Rodney Harrison formed a multi-agency 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, Heuermann was first mentioned as a possible suspect in the Gilgo Beach murder case after a New York state investigator identified him in a database, according to Suffolk County District Attorney Ray Tierney.

2023: Rex Heuermann arrested in some of the killings

On July 13, 2023, a suspect connected to some of the Gilgo Beach murders was taken into custody in New York City, marking the first arrest in the case, according to Harrison. He was transported back to Suffolk County Police headquarters in the hamlet of Yaphank on Long Island, the police commissioner said.

A day later, authorities identified the suspect as Heuermann, a registered architect who 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 murders, Tierney said during a news conference.

And authorities have hinted more charges could be coming, noting in court documents Heuermann has been tied to at least one other disappearance -- that of Brainard-Barnes -- of a woman who was later found dead.