Sandra Costilla was a 28-year-old Queens resident, originally from Trinidad and Tobago, whose body was found in a wooded patch of Southampton on November 20, 1993. Her murder went unsolved for more than 30 years. In June 2024, Suffolk County prosecutors charged Rex Heuermann, the accused Gilgo Beach serial killer, with her death, making the Sandra Costilla murder the earliest killing later attributed to him. Heuermann pleaded guilty in April 2026 and was sentenced two months later to life in prison without parole for killing eight women, Costilla among them.
How Her Body Was Found
Two waterfowl hunters came across Costilla on the morning of November 20, 1993, in a small stretch of woodlands off Fish Cove Road, just north of Noyac Road in the hamlet of North Sea within the town of Southampton.127east.com. Sandra Costilla Discovery Details She had disappeared the day before.2NewsNation. Timeline: Rex Heuermann Gilgo Beach
She was partially clothed, lying on her back with her arms stretched above her head and her legs uncovered. A shirt had been pressed over her head. Investigators counted 25 sharp force injuries to her face and body, which they believed had been inflicted after death. The body had been mutilated but not dismembered, and only what prosecutors later described as a “token effort” had been made to hide it.127east.com. Sandra Costilla Discovery Details
Three Decades Cold, With the Wrong Suspect in View
The case sat unsolved for years. For much of that time, investigators focused on convicted serial killer John Bittrolff, who had been tied to Costilla’s death but was never charged in connection with it.3News 12 Long Island. Police K-9 Searching in North Sea at Location of Cold Case Murder Attention shifted to Heuermann only as the wider Gilgo Beach investigation expanded. The specific evidence that eliminated Bittrolff has not been publicly detailed.
How Heuermann Was Linked to Her Killing
The breakthrough came from two hairs collected from Costilla’s body in 1993 and preserved for decades. Astrea Forensics, a California laboratory that works with degraded DNA, used whole genome sequencing to pull nuclear DNA from the rootless hair samples. That method can reconstruct a genetic profile from very short, damaged fragments where conventional DNA fingerprinting cannot.4NBC New York. Gilgo Beach Murder Rex Heuermann Trial DNA Evidence
Prosecutors said the hairs on Costilla were “statistically identical” to the DNA of Heuermann and a woman he lived with at the time of the murder.527east.com. IBDGem DNA Analysis Ruling The lab compared profiles using a statistical program called IBDGem, developed by Astrea co-founder Dr. Richard Green.6New York State Courts. People v. Rex Heuermann, Frye Hearing
Heuermann’s defense tried to keep the results out of court. Over nine days of Frye hearings between March and July 2025, attorney Michael Brown argued that whole genome sequencing and IBDGem lacked widespread scientific acceptance. Defense expert Dr. Dan Krane of Wright State University called the methods “wildly and unfairly prejudicial.” The defense also pointed to a mathematical error in Dr. Green’s published paper on IBDGem, which Green said was a typographical mistake not present in the software itself, and argued that the lab had not complied with FBI quality assurance standards.6New York State Courts. People v. Rex Heuermann, Frye Hearing
On September 3, 2025, Suffolk County Supreme Court Justice Timothy Mazzei ruled the DNA evidence admissible, finding the underlying science “generally accepted in the relevant scientific community.” The ruling covered hair evidence from Costilla and five other victims.7ABC News. Critical DNA Evidence Allowed in Gilgo Beach Serial Killer Case It was the first time such techniques had been permitted in a New York court.4NBC New York. Gilgo Beach Murder Rex Heuermann Trial DNA Evidence District Attorney Raymond Tierney called the ruling a “significant step in forensic DNA analysis.”8CNN. Gilgo Beach Rex Heuermann DNA Ruling
The Charge and Where Costilla Fit Among the Victims
On June 6, 2024, a superseding indictment charged Heuermann with second-degree murder in Costilla’s death, along with the murder of Jessica Taylor. Heuermann pleaded not guilty and was ordered held without bail.9Fox 5 New York. Gilgo Beach Murders Update: Rex Heuermann New Charges10ABC7. Gilgo Beach Suspect Rex Heuermann Expected in Court The charge pushed the timeline of his alleged killings back to 1993 and extended his suspected criminal span to more than three decades.
Costilla was killed years before any of the other identified victims. Karen Vergata followed in 1996, Valerie Mack in 2000, and Jessica Taylor in 2003. The four women whose remains were found along Ocean Parkway near Gilgo Beach in December 2010, known as the Gilgo Four, disappeared between 2007 and 2010. Prosecutors said Heuermann targeted sex workers and disposed of their bodies “over the course of 17 years.”11ABC News. Alleged Victims of Gilgo Beach Suspect Rex Heuermann
Her case was also a geographic outlier. Her body was found roughly 60 miles from Gilgo Beach, in North Sea rather than along the South Shore or in Manorville. Unlike Taylor and Mack, she was not dismembered. And investigators had spent years looking at a different suspect. Only the ability to extract usable DNA from hairs collected in 1993 tied her death to the same man responsible for the Gilgo Beach killings.
Plea and Sentence
On April 8, 2026, Heuermann pleaded guilty to seven counts of murder, including Costilla’s. He also admitted “intentionally causing the death of” an eighth victim, Karen Vergata, whose 1996 killing was covered by the plea agreement even though he was never formally charged in that case.12ABC7 New York. Gilgo Beach Suspected Serial Killer Rex Heuermann Expected to Plead Guilty When District Attorney Tierney asked in court whether he killed each victim in the same manner, by strangulation, Heuermann answered “Yes.” He admitted meeting all eight women, strangling them, and dumping their bodies at locations across Gilgo Beach, Manorville, and Southampton, and acknowledged using burner phones to contact them.13NBC News. Gilgo Beach Serial Killer Suspect Rex Heuermann Expected to Plead Guilty
On June 17, 2026, Justice Mazzei sentenced Heuermann to three consecutive life terms without parole for the first-degree murders of Melissa Barthelemy, Megan Waterman, and Amber Lynn Costello, plus a consecutive term of 100 years to life for the second-degree murders of Maureen Brainard-Barnes, Jessica Taylor, Sandra Costilla, and Valerie Mack. The sentence also covered the admitted killing of Vergata.14Suffolk County District Attorney’s Office. Gilgo Serial Killer Sentenced15Fox 5 New York. Rex Heuermann Sentenced After Pleading Guilty to Seven Murders16LI Herald. Sentenced to Life in Prison
Speaking to the victims’ families afterward, Tierney said, “For the families of these eight young women who have waited decades for this day, your voices have been heard. Rex Heuermann will now serve the rest of his life in prison for taking the lives of your loved ones.”17Suffolk Times. Gilgo Beach Serial Killer Rex Heuermann Gets Life Sentence With No Parole For Costilla’s family, the sentencing closed a case that had gone unanswered for 33 years.