Police were searching for a missing woman in 2010 when they began finding human remains in the scrub along a barrier island parkway near New York’s Gilgo Beach.

They almost immediately feared some were left by a serial killer.

Over the years, investigators used DNA analysis and other clues to identify a series of victims. In some cases, they were able to connect them to remains found elsewhere on Long Island years earlier.

Here is a timeline of the investigation that led to the arrest of Rex Heuermann, who pleaded guilty Wednesday to murdering seven women and admitted in court that he killed an eighth.

Skeletal remains and few clues

Nov. 20, 1993: Two hunters discover the body of Sandra Costilla, 28, in a wooded area of North Sea, a hamlet in the Hamptons. 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 the coast. Her name remains unknown to investigators until 2022, when new DNA analysis helps them make an identification. Vergata, 34, was involved in sex work when she vanished.

June 28, 1997: The partial remains of a woman are discovered inside a plastic tub in a state park in West Hempstead, New York. Investigators nickname her “Peaches” after a tattoo on her body. Her identity remains a mystery for many years, but in 2025 police identify her as Tanya Jackson, a U.S. Army veteran who was living in Brooklyn before she disappeared.

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 working as an escort.

July 9, 2007: Maureen Brainard-Barnes, 25, who had traveled to New York 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 Bronx apartment. She tells a friend she is going to see a man and will be back in the morning. Phone location data puts her last known location on Long Island. Days later, a man begins using Barthelemy’s mobile phone to make taunting phone calls to her relatives.

Disappearance leads to police search

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 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 that person he presumed was the client drove a Chevrolet Avalanche.

A surprise discovery

Dec. 11, 2010: A police officer and his dog discover human remains while conducting a training exercise along Ocean Parkway. Authorities initially suspect they may have located Gilbert, but are later able to identify the victim as Barthelemy.

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, while still looking for 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 a 2-year-old girl, later identified through DNA as Jackson’s daughter, Tatiana Dykes. 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 additional remains of Jackson along the beach parkway.

Dec. 13, 2011: Gilbert’s skeletal remains are discovered in a tidal marsh near Oak Beach. After an autopsy, Suffolk Police say she accidentally drowned.

A cold case thaws

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 is mobile phone location data suggesting 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.

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.

Dec. 17, 2024: An indictment is unsealed charging Heuermann in Mack’s death.

Dec. 18, 2025: A Florida man, Andrew Dykes, pleads not guilty to killing Tanya Jackson and Tatiana Dykes. Investigators say Andrew Dykes was Tatiana’s father and DNA evidence linked him to the crime. While in the end, the case was unconnected to the other Gilgo Beach deaths, the investigation benefited from the extra resources poured into the serial killer investigation, authorities say.

April 8, 2026: Heuermann pleads guilty to seven counts of murder, involving the killings of Barthelemy, Brainard-Barnes, Costello, Costilla, Mack, Taylor and Waterman. He also acknowledges in court that he killed Vergata. His sentencing is set for June 17.