Police have called the Gilgo Beach murders "one of the most consequential homicide investigations" in Long Island's history.
The search for missing sex worker Shannan Gilbert in 2010 led to the grisly discovery of 10 other bodies on a stretch of beach along the island's South Shore.
In 2023, a suspect was initially arrested in connection with several of the deaths in a case that now spans over two decades, with victims who were found in multiple locations on Long Island.
New York City architect Rex Heuermann was first charged with the murders of three women -- Melissa Barthelemy, Megan Waterman and Amber Costello -- whose bodies were found covered in burlap in December 2010, according to court records.
Heuermann was later charged in the death of a fourth victim, Maureen Brainard-Barnes, who was also found that month, according to court documents.
The four victims have become known as the "Gilgo Four"; the Craigslist escorts were found along the beach about 500 feet from each other, and all died by homicidal violence, according to officials.
In June 2024, the case took an even more shocking turn when Heuermann was charged with the murders of two more women -- including one dating back to 1993, well before the others were killed, and whose remains were located in Southampton, an hour east of Gilgo Beach.
Several months later, he was charged with the murder of a seventh woman whose remains were found in two locations, including near Gilgo Beach.
In April 2026, months before he was set to go to trial, Heuermann, 62, pleaded guilty to murdering those seven victims, and admitted to killing an eighth woman, during a 17-year killing spree.
Here's a timeline of the investigation and case against the married father of two.
Nov. 20, 1993
The body of 28-year-old Sandra Costilla is found in a wooded area in the Southampton hamlet, North Sea. Costilla, a native of Trinidad and Tobago, had been living in New York prior to her disappearance and murder, prosecutors said.
Feb. 14, 1996
Karen Vergata, 34, is last heard from before going missing. Authorities believe she worked as an escort at the time.
April 20, 1996
The partial remains of an unidentified woman, later determined to be Vergata, are located on Fire Island.
Nov. 19, 2000
The partial remains of Valerie Mack, a 24-year-old escort who disappeared while living in Philadelphia, are found in Manorville. A hunter's dog discovered her decapitated body in a wooded area. Her remains were bound with rope inside a black plastic bag which was wrapped with duct tape, according to a court filing. Both of her hands had been severed from her body and one of her legs was cut off.
July 2003
The remains of Jessica Taylor, a 20-year-old sex worker, are discovered in Manorville.
July 9, 2007
Maureen Brainard-Barnes, 25, is last seen alive in New York City, according to prosecutors.
July 10, 2009
Melissa Barthelemy, 24, is last seen alive in New York City, according to prosecutors.
May 1, 2010
Shannan Gilbert, 23, goes missing after fleeing from a client's home in Oak Beach, near Gilgo Beach, according to police. Her disappearance prompts several searches in the area.
June 6, 2010
Megan Waterman, 22, is last seen alive at the Holiday Inn in Hauppauge, New York, according to prosecutors.
Sept. 2, 2010
Amber Costello, 27, is last seen alive at her home in West Babylon, New York, according to prosecutors.
Dec. 11, 2010
An officer conducting a search for Gilbert with his police K9 along Ocean Parkway in Gilgo Beach -- near her last known location -- discovers a set of human remains that are later identified to be those of Barthelemy, police said.
Dec. 13, 2010
During a search of the area, police find the remains of Brainard-Barnes, Waterman and Costello within a quarter mile of where Barthelemy's remains were recovered, police said.
March 29, 2011
Amid the continued search for Gilbert, police find partial skeletal remains belong to Taylor several miles east of where the Gilgo Beach Four were found.
April 4, 2011
Police find three sets of remains along Ocean Parkway while searching for Gilbert.
The rest of Mack's remains are found about a mile and a half east of Taylor's remains and a little over 2 miles east of the Gilgo Four.
The remains of an unidentified female toddler are also located in the same area.
The remains of an unidentified man are also discovered closer to the remains of the Gilgo Four. Authorities said the person was about 17 to 23 years old, Asian, and had died five to 10 years before being discovered.
April 11, 2011
Two sets of remains are located off of Ocean Parkway in Nassau County, seven miles west of Gilgo Beach.
One set of remains is determined to be the mother of the female toddler discovered on April 4, 2011. Her partial remains were first discovered in 1997 in Hempstead Lake State Park. The victim, known as "Jane Doe No. 3," becomes known as "Peaches" due to a tattoo on her body.
The second set, known as "Jane Doe No. 7," are located on Tobay Beach and confirmed to belong to the victim whose remains were located on Fire Island in 1996.
Dec. 13, 2011
Gilbert's remains are found in marshland near Oak Beach. Her death is later ruled as an accidental drowning, though her family maintains they believe she was murdered.
January 2022
The Suffolk County District Attorney's Office creates a task force to conduct a comprehensive review of evidence in the investigation.
March 14, 2022
Heuermann first comes up as a suspect in the investigation, according to Suffolk County District Attorney Ray Tierney. Heuermann was tracked through his car, a Chevrolet Avalanche, according to court documents. A witness to Costello's disappearance reported seeing a Chevrolet Avalanche at Costello's home, court records stated.
July 13, 2023
Heuermann is arrested in Manhattan at his midtown office. Investigators matched DNA from hair recovered from the burlap used to wrap Waterman's body to leftover pizza crust Heuermann threw into a Manhattan garbage can in January 2023, according to court documents.
Detectives also tracked Heuermann through cellphone records, according to court records. Tierney said cellphone mapping led investigators to zero in on areas in midtown Manhattan and Massapequa Park, where Heuermann lives.
July 14, 2023
Defense attorney Michael Brown enters a not guilty plea on Heuermann's behalf at his arraignment for three counts of first-degree murder and three counts of second-degree murder. Heuermann is ordered held on no bail.
Aug. 4, 2023
Officials announce they have identified "Jane Doe No. 7," whose remains were first located on Fire Island in 1996 and then on Tobay Beach in 2011, as Vergata.
There are no charges at this time, Suffolk County District Attorney Raymond Tierney says.
June 6, 2024
Heuermann is charged with two more murders after investigators spent months combing through evidence taken from his family home and following searches of a wooded area in Manorville.
He is charged with the 2003 murder of Taylor, whose remains were found on Long Island in Gilgo Beach in March 2011, and in Manorville in July 2003, and the 1993 murder of Costilla, whose remains were found in North Sea, Long Island, according to court documents.
DNA, including a hair found on a drape under Taylor's body, ties Heuermann to both murders, according to prosecutors.
Costilla's murder was initially suspected to have been the work of a different killer, John Bittrolff, but advanced DNA now points to Heuermann, prosecutors said.
Heuermann pleads not guilty.
Dec. 17, 2024
Heuermann is charged with the murder of Mack. Prosecutors said they linked Heuermann to Mack's death in part through a mitochondrial DNA analysis of a female hair found on Mack's body, which matched the profiles of Heuermann's wife and daughter.
Prosecutors said they also linked Heuermann to Mack's death through evidence recovered on some of the 350 electronic devices they seized from him that include his "significant collection of violent, bondage and torture pornography" dating back to at least 1994. This online collection included images of mutilation and tying up women with ropes, two things prosecutors said are consistent with injuries inflicted on Mack and how she was bound, officials said.
Investigators said they found one document that they believe Heuermann used to "plan out" his kills. The document was created in 2000, the year Mack was killed. Heuermann also allegedly kept newspaper and magazine clippings about the Gilgo Beach serial killings in his Massapequa Park home, prosecutors said in a court filing.
He pleads not guilty to one count of second-degree murder in connection with Mack's death.
April 23, 2025
Authorities announce the identity of the victim known as "Peaches" -- Tanya Jackson, a 26-year-old Army veteran. Her toddler, known as "Baby Doe," is identified as 2-year-old Tatiana Dykes.
Nassau County Police Detective Captain Stephen Fitzpatrick says their deaths may not be connected to the Gilgo Beach serial murders.
Dec. 3, 2025
A man is arrested in Florida and subsequently indicted for second-degree murder for the 1997 killing of Jackson. The suspect, Andrew Dykes, is Tatiana's biological father, according to prosecutors.
Jan. 13, 2026
A judge says Heuermann will stand trial in September.
April 8, 2026
Heuermann pleads guilty to seven counts of murder, admitting to strangling the victims to death. He also admits to killing Vergata as part of a plea agreement, though is not formally charged with her death.
He has agreed to serve three consecutive life sentences followed by four consecutive sentences of 25 years-to-life, prosecutors say.
His sentencing is set for June 17.
ABC News' Aaron Katersky, Jon Haworth, Emily Shapiro, Josh Margolin, Mark Osborne and Mark Crudele contributed to this report.