A “demon that walks among us”. That is the phrase used by former Suffolk County Police Commission Rodney Harrison to describe Rex Heuermann, a married architect and father of two, allegedly living a double life. Heuermann was arrested and charged as the Gilgo Beach Serial Killer for viciously murdering multiple women and then calling some of their families afterward with the victims’ cell phones and taunting their grieving relatives.  A demon that walks among us…

Background

Between the mid-1990s and 2011, a serial killer was murdering petite twenty-year-old female sex workers and disposing of their remains along desolate spots of Ocean Parkway, near Gilgo Beach, Long Island.[1]  It wasn’t until 2010 that police would accidentally discover this gruesome burial ground. It was at that time that a twenty-three-year-old female, Shannon Gilbert, called the Suffolk County Police Department (SCPD) in the early morning hours from that same stretch of area, in fear for her life, begging the police to save her. The police did not save her, and she was never seen alive again.[2]

During a subsequent search for Shannon, an SCPD officer and his K9 partner inadvertently found the skeletal remains of four separate individuals. They had been bound and wrapped in burlap to obscure their decomposed bodies. Those women have become known as the “Gilgo Four”.  They were the first victims of the Gilgo Serial killer to be discovered. There would be more.

The investigation was dormant for more than a decade, and the police had no suspects. During that time, the SCPD and the Suffolk County District Attorney’s Office were in disarray, hounded by allegations of corruption. The Police Commissioner at the time, James Burke, and then District Attorney, Thomas Spota, were under investigation by the FBI and eventually were prosecuted. In light of that dysfunction, the federal and local governments did not work together in the Gilgo Beach Serial Killer investigation, and the case went cold.[3]

Things took a turn in 2018 when Geraldine Hart was appointed as the new Suffolk County police commissioner. A former FBI agent, Hart resurrected the investigation at the urging of the victim’s families. In 2022, Rodney Harrison succeeded her and continued her work, opening an interdepartmental agency task force to investigate the Gilgo murders.

Very quietly, the investigation began to yield results, and in July of 2023, Rex Heuermann, who lived in Massapequa Park, NY[4] was charged with the murders of three women. [5] Six months later, in January 2024, a superseding indictment added another victim.[6] Later that year, in June and December 2024[7], three additional victims were added to bring the total charges of murder against Heuermann to seven.

The Circumstantial Evidence against the Defendant

If the initial investigation can be described as a complete failure, the subsequent investigation, and the law enforcement personnel who assisted in it, was comprehensive and must be commended. The investigators uncovered a litany of evidence against Heuermann.

There is the consistent theme that the Defendant had unfettered time and opportunity to execute each of the murders charged – his family was either out of the state or he was living alone during the time frame of the murders. Then there is the physical description of an individual of interest provided by an eye-witness – one of a white male, 6 ½ feet in height, resembling an “ogre”, mid-40s with dark bushy hair and eyeglasses. This description eerily matches Heuermann. That eyewitness also described a green pickup, which matched a vehicle that had belonged to Heuermann at the time one of the victims went missing.

Cellphone records indicate the victims were contacted by a burner phone that pinged shortly before they disappeared, with the key locations of Heuermann’s residence in Massapequa Park and where the defendant worked in Manhattan. Heuermann owned a burner phone he frequently used to contact sex workers, and that was linked to a social media Tinder account. This geographic connection adds to the cumulative evidence against Heuermann.

Lastly, a document that prosecutors describe as a “planning document” that included purchasing stronger ropes and a litany of bondage pornography was found during the search of Heuermann’s home.

The DNA Evidence

The Heuermanns

When the circumstantial evidence pointed to Rex Heuermann, the police began a sixteen-month surveillance of him. During that time, police recovered bottles from outside Heuermann’s home. These bottles contained DNA belonging to Heuermann’s wife. The investigators surveilled Heuermann at his office in Manhattan and witnessed him eating pizza for lunch and then discarding the box in the garbage, which they recovered. From the pizza box, they were able to obtain a crust containing the defendant’s DNA.

Amber Costello

One of the “Gilgo Four”, Amber was last seen in 2010 by friends.  Her body was found on December 11, 2010, with the rest of the “Gilgo Four”. A female hair was found in the head area. DNA testing indicated that it was from Heumann’s wife or daughter.

Maureen Brainard-Barnes

Maureen was last seen on July 9, 2007. She is one of the Gilgo Four. A belt was recovered from her body, with a female human hair from the belt buckle. The DNA profiling revealed it to be from Heuermann’s wife.

Megan Waterman

Megan was last seen in 2010. Her body was found bound by duct tape. Two female human hairs were found on her body in her head area. DNA testing indicated that the hairs were from Heuermann’s wife or daughter.

Melissa Barthelemy

Hers was the first body to be found in the Gilgo Beach area. She was last seen in 2009. There appears to be no DNA evidence to connect Heuermann to Melissa’s death. Heuermann is alleged to have used Melissa’s cell phone to taunt her family on several occasions.

Jessica Taylor

One of the earliest victims, Jessica, was last seen in 2003. Later that year, her torso was found mutilated, her head decapitated, and her arms severed. The rest of her body parts were found in 2011 near the remains of the “Gilgo Four”. A male hair was recovered from a surgical drape that had been underneath the severed body parts. It was determined that the male hair and a swab of Heuermann were a 99.96% DNA match.

Sandra Costilla

Three hairs were recovered from Sandra. At the time of Ms. Costilla’s murder, Heuermann had been living with a woman who volunteered to provide her DNA to the investigators. That individual’s DNA matched one of the hairs found on Ms. Costilla. A second hair from the victim matched Heuermann.

Valarie Mack

In 2000, Valerie disappeared, and her mutilated body was discovered by hunters later that year in a plastic bag. Eleven years later, her skull, hands, and foot were found near the “Gilgo Four”.   Hairs recovered from the corpse matched the defendant’s wife and daughter, who share a mitochondrial DNA profile.

See the chart below for a summary of the DNA results.

The DNA Technology Used

The particular DNA technique used to connect the victims to Heuermann has never been used to prosecute a defendant in a New York State Court before. The defense questions the technology used to determine the DNA matches between Heuermann and the Gilgo victims.

DNA technology was first used in 1986 in England.  By the 1990s, DNA evidence was used by the FBI. That type of DNA evidence is called short tandem repeat, or STR for short. It uses repeated sequences in our DNA that are unique to each individual and is now widely accepted as reliable science.

The technique used in the Heuermann case is called single nucleotide polymorphism or “SNIPS” for short. This technique is different than STR and looks for individual markers instead of repeating patterns. With SNIPS, you look for a single change in a DNA nucleotide sequence. STR requires larger amounts of DNA, but with SNIPS, you can get a lot more with a lot less.

SNIPS is more common than you think. It is used in genealogy websites such as ancestry.com, and the New York City Office of Chief Medical Examiner (OCME) has used DNA technology to identify victims’ remains from 9/11.

Although never used in a New York criminal trial to convict a suspect, it has been used in other jurisdictions, such as Idaho, where it helped convict David Dalrymple of a 40-year cold case where 9-year-old Daralyn Johnson was abducted, sexually abused, and killed.[8]

FRYE

Heuerman’s attorneys have asked the presiding judge to preclude expert testimony related to the DNA results. They say the SNIPS technique used by investigators is not reliable. A Frye hearing was held on March 28, 2025, in Heuermann’s case to determine the issue.

A Frye hearing is one where a judge determines if science is generally accepted as reliable by other experts in the field. If this were federal court, the judge would hold a Daubert hearing, the federal equivalent to Frye.

At issue in the Heuermann case is that the hairs that were found on the decomposed bodies were there for years. DNA degrades over time. The defense claims that SNIPS is not science but “magic”.  But remember, it wasn’t that long ago that STR testing was new.[9] Courts do have incentives to allow new technology to be admitted. Jurors can still disregard the testimony, and a criminal defense attorney certainly can bring an expert to challenge its weight.

During the Heuermann Frye hearing, an expert for the prosecution testified that the DNA testing at issue was “widely accepted” in the scientific community and it was “embarrassing for our criminal justice system that a method like this wasn’t the state-of-the-art years ago”. On cross-examination by the defense attorney, the witness clarified that the “science” was widely accepted by the genetics community but not by the forensic scientific community. A ruling has not yet been issued.  If the judge determines that the SNIPS technology is generally accepted as reliable in the scientific community, then the Heuermann jury will be permitted to evaluate this evidence at the murder trial.

Conclusion

Should the DNA results be admitted, it is hard to argue against the cumulative effect against Heuermann. It is likely a jury would agree with Commissioner Harrison’s assessment that Heuermann is the Gilgo Beach Serial Killer and a demon that walked among us.  If a jury is precluded from seeing the DNA results, well, that “demon” may very well soon walk among us again.

[1] An area not far from my home and is now the Jones Beach bicycle path and one I ride regularly.

[2] Shannon Gilbert’s remains were found approximately one year later, but police ruled that she was not the victim of the Gilgo Beach serial killer and that she had drowned in a marsh. Her family has disputed that conclusion.  For an excellent movie about the tragic events surrounding Ms. Gilbert, see Lost Girls on Netflix.

[3] It is also thought that there was a lack of motivation because the victims in the case were sex workers.

[4] Massapequa Park is just across the bay from Gilgo and about a 15-minute car ride to the dumping area of Ocean Parkway.

[5] Melissa Barthelemy, Megan Waterman, Amber Costello,

[6] Maureen Brainard-Barnes (The Gilgo Four)

[7] Sandra Costilla, Jessica Taylor, Valerie Mack

[8] https://www.idahostatesman.com/news/local/crime/article292070495.html

[9] As of today, a whole genome sequence can be done for around $600 with many providers offering prices ranging from $399 to $999 depending on the company and package chosen; this represents a significant drop from the previous cost of millions of dollars to sequence a human genome