Woman who resided in Clearwater among victims of accused Long Island serial killer

TAMPA, Fla. (WFLA) — Almost 13 years ago, police in Long Island made a series of disturbing discoveries after the remains of 11 people were found along a beach highway.

Among these victims was 27-year-old Amber Lynn Costello, who police said moved to New York from Clearwater, Florida, before her death.

According to a 2011 article from the Tampa Bay Times, Costello had originally grown up in North Carolina, but lived in Pinellas County for several years.

Costello, like many of the victims in what would be known as the Gilgo Beach murders, was a sex worker who met clients through Craiglist and Backlist.

She resided with three other people at a house in West Babylon, New York. According to Suffolk County police, Costello and her housemates struggled with heroin addiction, and while she had completed a 28-day rehab program, she relapsed shortly before her disappearance.

Despite her personal problems, people who knew her called her a good person who got mixed up with the wrong crowd.

“She was hyper, happy and energetic,” said Cherie Malpass, Costello’s cousin-in-law, in a 2011 interview with the Tampa Bay Times. “She never did cause trouble or anything like that.”

Police said Costello was last seen alive on Sept. 2, 2010, when she went to meet a client who was supposed to pick her up from her home. However, authorities said Costello did not take her cellphone and was not reported missing.

No one had seen any sign of the 27-year-old for two months until Dec. 13, 2010, when her remains were found along Ocean Parkway near Gilgo Beach while authorities searched for another missing woman, Shannan Gilbert.

Gilbert’s disappearance is what triggered the discovery of numerous other murders along the Parkway. Her body was found about 3 miles away from the other 10 sets of human remains, authorities said.

These victims included:

• Melissa Barthelemy — went missing on July 12, 2009
• Maureen Brainard-Barnes — last seen alive in early June 2007
• Amber Lynn Costello — last seen alive on Sept. 2, 2010
• Megan Waterman — last seen alive in June 2010
• Jessica Taylor — Her remains were first found on July 26, 2003, with the rest found on March 29, 2011, along Ocean Parkway.
• Valerie Mack — Her remains were located in Manorville in 2000 and in Oak Beach in 2011,.
• Originally a Jane Doe, her remains were identified by genetic genealogy in 2020.
• A John Doe, described as an Asian man whose skeleton was found along Ocean Parkway.
• An unidentified female toddler, whose remains were found near Mack’s remains.
• The mother of the toddler, another Jane Doe, who was referred to as “Peaches” due to “a bitten heart-shaped tattoo of a peach on her body.” Her remains were first found in Hempstead Lake State Park in 1997.

The serial killings stuped authorities until July 14, 2023, when officials announced the arrest of a suspect in their deaths.

In a Friday press conference, Suffolk County District Attorney Raymond A. Tierney said architect Rex Heuermann, who lived across the bay from where the victims’ remains were found, was indicted in the murders of Costello, Barthelemy, and Waterman.

“When I took office in 2022, I made Gilgo a priority,” Tierney said.

According to the district attorney, the women disappeared between July 2007 and September 2010. Tierney said the women’s remains were bound on the head, chest, and legs with camouflage burlap, typically used for hunting, in order to conceal them.

He said DNA evidence taken from abandonment samples also played a major role in identifying Heuermann as a suspect.

The district attorney also said Heuermann had a burner phone that he used to communicate with each victim and would discard the cell phones after each murder.

However, after examining the cell phone pings on four cell tours they were able to track the suspect to Massapequa Park, where he lived. Tierney said each murder happened while Heuermann’s wife and children were out of state.

Further investigation found that the architect had over 200 Google searches regarding the Gilgo murders, which Tierney said led to the investigation being held in secret to not alert the defendant.

“In addition to those Gilgo search, he also impulsively searching pictures of the victims, but not only pictures of the victims, pictures of their relatives, their sisters, their children, and he was trying to locate those individuals,” he said.

Heuermann also had torture pornography and depictions of sexual assault in his search history, according to authorities. Tierney said the architect was also still seeking the services of sex workers, which made investigators nervous.