Prosecutors have now charged a Long Island architect, Rex Heuermann in seven killings.
Here is a timeline of the investigation:
Nov. 20, 1993: Two hunters discover the body of Sandra Costilla, 28, in a wooded area of North Sea, a hamlet in the Hamptons near the eastern end of Long Island. Costilla had been living in New York City.
April 20, 1996: The partial remains of Karen Vergata are discovered on Fire Island, a barrier beach off Long Island's southern coast. Her name remains unknown to investigators until 2022, when new DNA analysis helps them make an identification. Vergata, 34, was last in contact with her family on Feb. 14, 1996. She was involved in sex work when she vanished.
June 28, 1997: The partial remains of a woman, nicknamed “Peaches” by investigators after a tattoo on her body, are discovered stuffed inside a plastic tub in a state park in West Hempstead, New York. Her identity remains unknown.
September 2000: The partial skeletal remains of Valerie Mack, who had been working as an escort in Philadelphia, are found in a wooded area in Manorville, New York. Mack, 24, was last seen by her family in the spring or summer of that year in Port Republic, New Jersey.
July 26, 2003: The partial skeletal remains of Jessica Taylor are discovered in a wooded area of Manorville. She was 20 when she vanished and had been an escort working in New York City.
July 9, 2007: Maureen Brainard-Barnes, 25, who had traveled to New York City from her home in Norwich, Connecticut, for sex work, is last heard from by a friend. She says she is leaving her hotel to meet a client. Investigators later say cellphone records showed her phone was last used on Long Island.
July 10, 2009: Melissa Barthelemy, a 24-year-old sex worker, is last seen at her apartment in the Bronx. She tells a friend she is going to see a man and will be back in the morning. Cellphone location data puts her phone's last known location on Long Island. Days later, a man begins using Barthelemy’s mobile phone to make taunting phone calls to her relatives.
May 1, 2010: Shannan Gilbert, a sex worker, disappears in the barrier island community of Oak Beach, New York, after fleeing the house of a client and banging on a neighbor’s door. In a recorded 911 call, she tells a dispatcher that people are after her, but she can also be heard refusing offers of help. Her pimp, the client and his neighbor all tell police she appeared disoriented and ran into the night on her own.
June 6, 2010: Megan Waterman, 22, who had traveled to Long Island from Maine for sex work, is last seen at a motel in Hauppauge, New York.
Sept. 2, 2010: Amber Lynn Costello, 27, is last seen leaving her home in West Babylon to meet with a sex work client. A male friend later tells investigators he noticed a Chevrolet Avalanche, presumably driven by the client.
December 11, 2010: A police officer and his dog discover Barthelemy's remains while conducting a training exercise along Ocean Parkway.
Dec. 13, 2010: Police find the bodies of Costello, Brainard-Barnes and Waterman on the same quarter-mile stretch of Ocean Parkway where Barthelemy’s remains were located.
Dec. 14, 2010: Suffolk County Police Commissioner Richard Dormer publicly announces the discovery of the bodies and says a serial killer might be to blame. Police expand the search, looking for additional remains or any sign of Gilbert.
March 29, 2011: Some of Taylor’s remains are discovered along Ocean Parkway.
April 4, 2011: Additional remains of Valerie Mack are found along Ocean Parkway. Near those remains, investigators also find the remains of an unidentified female toddler, later identified through DNA as the daughter of “Peaches.” Elsewhere on the parkway, investigators discover the remains of an Asian male. Investigators estimate he died five to 10 years earlier and was in his late teens or early 20s. He still has not been identified.
April 11, 2011: Additional remains of Vergata are discovered along Ocean Parkway, several miles west of Gilgo Beach. Police also find remains belonging to “Peaches” along the beach parkway.
Dec. 13, 2011: Gilbert’s skeletal remains are discovered in a tidal marsh near Oak Beach. After an autopsy and further investigation, Suffolk Police say she most likely accidentally drowned. Her family still suspects she was slain.
January 2022: The Suffolk County district attorney convenes a new task force to investigate the Gilgo Beach killings.
July 13, 2023: Investigators arrest Heuermann and charge him with murdering Costello, Waterman and Barthelemy. The key evidence in the case is mobile phone location data suggesting that Heuermann and the women were in the same places at some of the same times, and traces of DNA found on the remains.
Jan. 16, 2024: Heuermann is charged in the death of Brainard-Barnes. Prosecutors say a hair found with her corpse is genetically similar to a DNA sample from Heuermann's wife.
Late April 2024: Police conduct a new, multiday search of a wooded area in Manorville where Taylor and Mack's remains were discovered more than a decade earlier. They also perform a new search on the spot where Costilla's body was discovered in 1993.
May 20, 2024: Investigators launch a new search of Heuermann's home. It lasts nearly a week.
June 6, 2024: Heuermann is charged with murdering Costilla and Taylor. He pleads not guilty.
Dec. 17, 2024: An indictment is unsealed charging Heuermann in Mack's death. Heuermann pleads not guilty.