Gilgo Beach killings: What to know about judge's DNA decision and its impact on trial of suspect Rex Heuermann

A Suffolk County Supreme Court judge ruled Wednesday that hair and DNA evidence connecting alleged Gilgo Beach serial killer Rex A. Heuermann to the slayings of six women will be allowed as evidence at the architect's future trial.

The groundbreaking DNA analysis, which uses techniques and methods that had not been tested in New York courts, had been challenged by Heuermann's defense, which argued the technology was in its "infancy" and could not be relied upon.

Here's everything to know about the evidence, the ruling and what it means for Heuermann's case.

What does the evidence show and how was it obtained?

Prosecutors said a DNA analysis, conducted by Astrea Forensics, a California laboratory, linked Heuermann, his ex-wife Asa Ellerup, and their adult daughter, Victoria Heuermann, to hair strands found on the remains of six of the seven Gilgo victims that Heuermann's been charged with killing. Prosecutors said Heuermann killed the women when his wife and children were out of state.

Astrea's technique, known as IBDGem, used a complex statistical analysis to compare the DNA of Heuermann and his family to rootless hair samples found on the victims' bodies.

IBDGem's analysis method compared the evidence sample DNA to an open-source repository of about 2,500 human genomes known as the 1,000 Genomes Project. The method, prosecutors said, has been widely adopted in fields such as human identification, disease genetics and prenatal care, and is used for critical medical decisions.

Prosecutors said the nuclear DNA evidence was later corroborated by a second lab's mitochondrial DNA analysis, which is commonly used in courts.

What were the objections from Heuermann's defense?

Heuermann’s defense had tried to have the DNA evidence thrown out, arguing the new technology and statistical analysis was not widely accepted in the scientific community, and therefore did not meet the legal threshold for admission into New York courts.

Danielle Coysh, one of Heuermann's defense attorneys, also argued that Richard Green, co-founder of the lab, has a financial stake in promoting IBDGem, creating a conflict of interest.

The methodology employed by Astrea, Coysh argued in court papers, has only been used in one previous criminal trial in Idaho, helping to convict a suspect last year in the 1982 rape and murder of a 9-year-old girl.

What did the judge say?

Suffolk County Supreme Court Justice Timothy Mazzei held a series of hearings between March and July — referred to in legal parlance as the Frye test — to vet IBDGem, Astrea Forensics and the doctors performing the testing and analysis.

The Frye standard of admissibility dictates that to be admitted at trial, the scientific method be generally accepted by the scientific community — a standard Mazzei said the prosecution met. 

"This court agrees that while IBDGem is a relatively new software system, the principles used within it, which are behind the math and data collected, are accepted as reliable in the scientific community," Mazzei wrote in his 29-page ruling for the prosecution.

What does the ruling mean for Heuermann's trial?

The ruling means the DNA results, along with the witness testimony pertaining to how the evidence was obtained and verified, are admissible at trial.

Heuermann, who remains in a Suffolk jail pending his trial, has pleaded not guilty to the murder of seven women, but the DNA testing used only applies to six victims — Maureen Brainard-Barnes, Megan Waterman, Amber Lynn Costello, Sandra Costilla, Jessica Taylor and Valerie Mack.

What happens next?

Immediately after Mazzei issued his ruling, the defense filed a motion arguing the work performed by Astrea, which is unaccredited, was in violation of New York State public health law and therefore should be deemed unreliable.

Defense attorney Sabato Caponi wrote in a motion that labs lacking New York State Department of Health permits are prohibited from accepting specimens and the DNA evidence should therefore not be allowed at trial.

By Robert Brodsky

robert.brodsky@newsday.com@BrodskyRobert

Robert Brodsky is a breaking news reporter who has worked at Newsday since 2011. He is a Queens College and American University alum.