Many of the victims' remains were found over a period of months in 2010 and 2011 during a police search of the area along Ocean Parkway, a road near the remote beach town of Gilgo on Long Island in Suffolk County, New York.

Rex Heuermann, a Manhattan architect and resident of Massapequa Park, Long Island, is accused of murdering seven women – all of the Gilgo Four victims: Megan Waterman, Melissa Barthelemy, Amber Costello, and Maureen Brainard-Barnes – as well as Jessica Taylor, Sandra Costilla, and Valerie Mack.

[14] Authorities began to seriously consider Heuermann as a suspect in March 2022 after discovering that a dark green first generation Chevrolet Avalanche vehicle registered in his name had been linked to one of the killings by a witness.

Her body was found in November 1993 by hunters in a wooded area in North Sea, Long Island, approximately 60 miles northeast of Gilgo Beach.

Costilla is the earliest known victim in the set of murder charges against Heuermann, indicating that he allegedly began killing in the 1990s or earlier, and that he disposed of bodies in locations beyond the Gilgo Beach area.

[38][39] Waterman was reported missing by family members on June 8, 2010, after uncharacteristically failing to check in on her three-year-old daughter who had been left in their care.

[35][24] Costello, 27, of West Babylon, New York, a small town ten miles north of Gilgo Beach, was a sex worker who went missing on September 2, 2010.

[40] Costello's roommate gave police a description of the unknown client and the first generation Chevrolet Avalanche he was driving, which more than a decade later prompted the investigation into Rex Heuermann as a possible suspect.

[24] Born in Charlotte and raised in Wilmington, North Carolina, Costello was living in West Babylon with several other heroin addicts when she disappeared.

[41][42] At the time of her disappearance, Costello's family believed that she was in a residential drug rehabilitation center, so she was not immediately reported missing when she stopped responding to messages and phone calls.

[52] A head, right foot, and hands found on April 4, 2011, were at first determined to have belonged to an unidentified victim, dubbed "Jane Doe No.

[52] On May 28, 2020, police announced that the remains had been identified as Valerie Mack, who had last been seen by family members in the spring or summer of 2000 in the area of Port Republic, New Jersey.

[55] The dismembered remains of Valerie Mack and Jessica Taylor were both disposed of in a similar manner, and in the same part of Manorville, suggesting a link.

On July 26, 2003, her torso was discovered 45 miles (72 km) east of Gilgo Beach in Manorville, New York;[58] these remains were identified by DNA analysis later that year.

[67][68][69] Fifteen years later, on April 11, 2011, her skull and several of her teeth were recovered at Tobay Beach, the second set of remains to be discovered in Nassau County that day.

"[68] On June 28, 1997, the dismembered torso of an unidentified young African-American woman was found at Hempstead Lake State Park, in the town of Lakeview, New York.

[73] On April 11, 2011, police in Nassau County discovered dismembered skeletal human remains inside a plastic bag near Jones Beach State Park.

[73] DNA analysis also identified "Peaches" as the mother of "Baby Doe"; she was found wearing gold jewelry similar to that of her daughter.

She was last seen a short time later banging on the front door of a nearby Oak Beach residence and screaming for help before running off into the night.

[82] On November 15, 2012, a lawsuit was filed by her mother, Mari Gilbert, against the Suffolk County Police Department in the hopes of getting more answers about what happened to her daughter the night she went missing.

The officer based his choice of search area on FBI data indicating that dumped bodies are frequently found close to roadways.

Despite thick vegetation and a light layer of snow, Mallia's cadaver dog alerted to a scent which the pair tracked to a skeleton wrapped in disintegrating burlap.

The bodies of the four victims – Maureen Brainard-Barnes, Melissa Barthelemy, Megan Waterman, and Amber Costello – were found approximately 500 feet (150 m) from each other.

[88] Police have stated that the death of Gilbert, whose disappearance triggered the search during which the first set of bodies was found, was due to drowning, and is likely unrelated to the Long Island serial killer case.

[96] On May 6, 2020, the New York State Supreme Court ordered Suffolk County Police to release Gilbert's 911 call recording, denying their request to withhold it after more than 10 years.

[99][100] In June 2019, a proposal was made to use genealogy to identify the unidentified victims and possibly the killer in the Gilgo Beach case.

[103] The Suffolk County police did not comment on the prosecutor's statement due to the active homicide investigation of the Gilgo Beach murders.

[104] Bittrolff lived in Manorville, 30 miles (48 km) from where the torsos of Gilgo Beach victims Jessica Taylor and Valerie Mack were recovered.

[106] Rex Heuermann has been indicted in relation to the murders of Amber Lynn Costello, Megan Waterman, Melissa Barthelemy, Maureen Brainard-Barnes, Sandra Costilla, Jessica Taylor, and Valerie Mack.

[107] According to The New York Times in 2011, the perpetrator was most likely a white male in his mid-twenties to mid-forties who was very familiar with the South Shore of Long Island and had access to burlap sacks used to hold the bodies for disposal.