Geneticist says techniques for analyzing DNA in case of alleged Gilgo serial killer Rex Heuermann are 'widely accepted'
A top population geneticist told a Suffolk judge the nuclear DNA techniques and likelihood ratios linking degraded hair samples found at the Gilgo Beach crime scenes to suspect Rex A. Heuermann are "widely accepted" in the scientific community, as testimony in the first pre-trial hearing in the high profile case began in Riverhead Friday.
"It's embarrassing for our criminal justice system that a method like this wasn't the state of the art years ago," witness Kelley Harris testified, as she read from her peer review of the methodology used by the outside laboratory working with investigators on the cases.
Harris, an associate professor of genome sciences at the University of Washington, testified that in the review, she had described the tool, known as IBDGem, as "elegant and powerful."
Harris was the first witness called to testify in the hearing, in which prosecutors are seeking to have Suffolk Supreme Court Justice Timothy Mazzei approve the admissibility of the whole genome sequencing DNA analysis from a California lab, whose methods have never been tested in New York courts.
The Heuermann defense team has sought to have the evidence developed from the degraded hair samples and compared by Astrea Forensics with the DNA of Heuermann and his family members excluded, arguing the science has not been generally accepted or appropriately peer reviewed.
During cross-examination Friday, defense attorney Michael J. Brown, of Central Islip, asked Harris if she was referring to the forensic science community when she stated that IBDGem was widely accepted. Harris clarified that it is generally accepted in population genetics, but not in forensics, which pertains to the investigation of crimes.
Harris said she had never previously testified in court and is not herself a forensics expert. She noted during cross-examination that she was recommended to the prosecution by Richard Green, the founder of Astrea, who she has collaborated with in the past. Brown said other locally based experts could have been called to testify, but theorized they might not have been willing to support the science.
Brown also called into question the thoroughness of the peer review Harris wrote for Green's IBDGem paper, asking her to confirm it was just five paragraphs long moments after she testified that peer reviews can sometimes be five pages long.
Harris also testified that she has never visited Astrea or looked at the source code used by the lab. Her peer review of the methodology was based on summarized data included in Green's paper, she told the court. She also conceded that Astrea's methodology is not used by any crime lab anywhere in the country.
Brown noted that other genetic databases commonly used in criminal investigations draw from larger population pools than the 1,000 Genomes project, the catalog used by IBDGem. The defense attorney said outside of court that the smaller pool causes the likelihood ratios under the Astrea methodologies to be "off the charts" and inaccurate.
Harris pushed back on the idea that the smaller pool in 1,000 Genomes limits the effectiveness of the analysis. "It contains all the common [genetic] variations present in the pool of suspects in our criminal justice system," Harris said.
Harris said she believed the analysis done by Astrea is scientifically accurate and prosecutors have noted that Astrea's findings were corroborated by a second lab's mitochondrial DNA analysis, which has become commonly used in courts.
The hearing marked the first time Heuermann, 61, of Massapequa Park, has made more than a brief appearance in court, as he spent the entire day at the defense table, just feet away from the audience, which included his wife and daughter. Heuermann looked out and scanned the audience each time he made his way back into the courtroom. During testimony, he shuffled through relevant research papers and looked ahead at a monitor showing exhibits that were being discussed.
The hearing will continue when the defense calls its second witness Wednesday, Mazzei said. It was unclear who that witness will be and Suffolk District Attorney Ray Tierney declined to comment outside of court.
Prosecutors will likely call four witnesses on four separate dates, Tierney said prior to the start of the hearing. Brown declined to say if the defense will call witnesses.
Harris gave testimony specific to the different types of genome sequencing methods used by researchers and the likelihood ratios they generate. She was not presented as an expert witness to provide testimony on the specific samples used to connect Heuermann to his alleged victims.
The Frye standard for admissibility of scientific evidence, the standard used in New York, requires that "before being admitted, the prosecutor must prove the evidence's general acceptance by the scientific community," according to the National Institute of Justice.
Throughout questioning by Assistant District Attorney Nicholas Santomartino, Harris declared certain methods and techniques, which prosecutors have said were used by Astrea, to be widely accepted in comparing degraded samples with more robust data.
The January defense motion seeking to bar the evidence pointed to grand jury testimony from Suffolk County Crime Lab forensic scientist Clyde Wells, who the defense argues repeatedly told the grand jury the "rootless hairs were unsuitable for nuclear DNA testing."
But prosecutors have said Astrea’s techniques later helped investigators connect Heuermann and family members with the hairs located at the crime scenes of Maureen Brainard-Barnes, Megan Waterman, Amber Costello, Sandra Costilla, Jessica Taylor and Valerie Mack, six of the seven alleged victims in the indictment charging Heuermann with first- and second-degree murder.
The lab found hair discovered on items recovered from the Costilla, Waterman and Taylor crime scenes are statistically likely to have come from Heuermann himself, according to the prosecution's bail application filed in June.
The lab linked other hairs found when the bodies were recovered between 1993 and 2011 to Heuermann’s wives and daughter, which prosecutors allege were transferred from another surface during the killings.
Prosecutors have said the evidence linking Heuermann to a seventh alleged victim, Melissa Barthelemy, does not include DNA.
Heuermann has denied any involvement in the deaths since his arrest in the decades-old case in July 2023.
A top population geneticist told a Suffolk judge the nuclear DNA techniques and likelihood ratios linking degraded hair samples found at the Gilgo Beach crime scenes to suspect Rex A. Heuermann are "widely accepted" in the scientific community, as testimony in the first pre-trial hearing in the high profile case began in Riverhead Friday.
"It's embarrassing for our criminal justice system that a method like this wasn't the state of the art years ago," witness Kelley Harris testified, as she read from her peer review of the methodology used by the outside laboratory working with investigators on the cases.
Harris, an associate professor of genome sciences at the University of Washington, testified that in the review, she had described the tool, known as IBDGem, as "elegant and powerful."
Harris was the first witness called to testify in the hearing, in which prosecutors are seeking to have Suffolk Supreme Court Justice Timothy Mazzei approve the admissibility of the whole genome sequencing DNA analysis from a California lab, whose methods have never been tested in New York courts.
WHAT NEWSDAY FOUND
- A top population geneticist testified at trial that techniques used to link degraded hair samples found at the Gilgo Beach crime scenes to suspect Rex Heuermann are "widely accepted" in the scientific community.
- Prosecutors are seeking to have Suffolk Supreme Court Justice Timothy Mazzei approve the admissibility of the genome sequencing DNA analysis from a California lab, whose methods have never been tested in New York courts.
- The Heuermann defense team argued the science has not been generally accepted or appropriately peer reviewed.
The Heuermann defense team has sought to have the evidence developed from the degraded hair samples and compared by Astrea Forensics with the DNA of Heuermann and his family members excluded, arguing the science has not been generally accepted or appropriately peer reviewed.
During cross-examination Friday, defense attorney Michael J. Brown, of Central Islip, asked Harris if she was referring to the forensic science community when she stated that IBDGem was widely accepted. Harris clarified that it is generally accepted in population genetics, but not in forensics, which pertains to the investigation of crimes.
Harris said she had never previously testified in court and is not herself a forensics expert. She noted during cross-examination that she was recommended to the prosecution by Richard Green, the founder of Astrea, who she has collaborated with in the past. Brown said other locally based experts could have been called to testify, but theorized they might not have been willing to support the science.
Kelley Harris, a DNA expert, called to testify at Suffolk County Court in Riverhead Friday. Credit: Newsday/James Carbone
Brown also called into question the thoroughness of the peer review Harris wrote for Green's IBDGem paper, asking her to confirm it was just five paragraphs long moments after she testified that peer reviews can sometimes be five pages long.
Harris also testified that she has never visited Astrea or looked at the source code used by the lab. Her peer review of the methodology was based on summarized data included in Green's paper, she told the court. She also conceded that Astrea's methodology is not used by any crime lab anywhere in the country.
Brown noted that other genetic databases commonly used in criminal investigations draw from larger population pools than the 1,000 Genomes project, the catalog used by IBDGem. The defense attorney said outside of court that the smaller pool causes the likelihood ratios under the Astrea methodologies to be "off the charts" and inaccurate.
Harris pushed back on the idea that the smaller pool in 1,000 Genomes limits the effectiveness of the analysis. "It contains all the common [genetic] variations present in the pool of suspects in our criminal justice system," Harris said.
Harris said she believed the analysis done by Astrea is scientifically accurate and prosecutors have noted that Astrea's findings were corroborated by a second lab's mitochondrial DNA analysis, which has become commonly used in courts.
The hearing marked the first time Heuermann, 61, of Massapequa Park, has made more than a brief appearance in court, as he spent the entire day at the defense table, just feet away from the audience, which included his wife and daughter. Heuermann looked out and scanned the audience each time he made his way back into the courtroom. During testimony, he shuffled through relevant research papers and looked ahead at a monitor showing exhibits that were being discussed.
The hearing will continue when the defense calls its second witness Wednesday, Mazzei said. It was unclear who that witness will be and Suffolk District Attorney Ray Tierney declined to comment outside of court.
Prosecutors will likely call four witnesses on four separate dates, Tierney said prior to the start of the hearing. Brown declined to say if the defense will call witnesses.
Harris gave testimony specific to the different types of genome sequencing methods used by researchers and the likelihood ratios they generate. She was not presented as an expert witness to provide testimony on the specific samples used to connect Heuermann to his alleged victims.
The Frye standard for admissibility of scientific evidence, the standard used in New York, requires that "before being admitted, the prosecutor must prove the evidence's general acceptance by the scientific community," according to the National Institute of Justice.
Throughout questioning by Assistant District Attorney Nicholas Santomartino, Harris declared certain methods and techniques, which prosecutors have said were used by Astrea, to be widely accepted in comparing degraded samples with more robust data.
The January defense motion seeking to bar the evidence pointed to grand jury testimony from Suffolk County Crime Lab forensic scientist Clyde Wells, who the defense argues repeatedly told the grand jury the "rootless hairs were unsuitable for nuclear DNA testing."
But prosecutors have said Astrea’s techniques later helped investigators connect Heuermann and family members with the hairs located at the crime scenes of Maureen Brainard-Barnes, Megan Waterman, Amber Costello, Sandra Costilla, Jessica Taylor and Valerie Mack, six of the seven alleged victims in the indictment charging Heuermann with first- and second-degree murder.
The lab found hair discovered on items recovered from the Costilla, Waterman and Taylor crime scenes are statistically likely to have come from Heuermann himself, according to the prosecution's bail application filed in June.
The lab linked other hairs found when the bodies were recovered between 1993 and 2011 to Heuermann’s wives and daughter, which prosecutors allege were transferred from another surface during the killings.
Prosecutors have said the evidence linking Heuermann to a seventh alleged victim, Melissa Barthelemy, does not include DNA.
Heuermann has denied any involvement in the deaths since his arrest in the decades-old case in July 2023.
Grant Parpan covers Suffolk County courts and federal courts for Newsday. A Long Island native, he joined Newsday in 2022.
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