It's a match! An analysis of the admissibility of novel scientific evidence in the Gilgo Beach murder trial
By Karen Czapkowski ‘27
Background:
The Gilgo Beach murder case began when a woman named Shannan Gilbert went missing. While searching for Shannan amongst the Long Island marshes, investigators found four new bodies. The women were all wrapped in burlap near Gilgo Beach. They suspected that the same person was behind the death of the four women. Not only was the M.O. (modus operandi) of the deaths similar, the women killed were also part of that pattern: They were all petite, in their 20s, and were all online escorts. And so the police began to hunt for the killer of the Gilgo Four.
While conducting the investigation, investigators found seven other sets of remains. Amber Costello was one of those, and she quickly became an important victim in the case. Costello, like the other girls, was an escort. After she disappeared, her roommate, Dave Schaller, gave investigators key identifying information of the suspect. Schaller saw the man who had picked Costello up. He described him as ogre-like, driving a Chevrolet Avalanche.
Investigators eventually found Shannan Gilbert’s body on December 13th, 2011. It is believed that her death was an accident, and that she ran into the marsh and drowned. However, the investigation into her death uncovered 11 other people who were murdered. For years after their discovery, the murderer of these victims was unknown. The case went stagnant until 2022, when the Suffolk County Police Department formed a new task force to finally put an end to the investigation. It only took the investigators six weeks to identify a suspect. The testimony from Amber Costello’s roommate was key in this. The description of the man, coupled with the make and model of the car, led investigators to their suspect: Rex Heuermann.
The police began to follow Heuermann at this point, searching for more evidence to see if their suspect was the right person. They managed to recover a pizza box from Heurmann’s trash which they obtained his DNA from. It matched one of the hairs that was discovered on one of the Gilgo fours’ bodies.
Which brings forth the current issue. The defense had filed for a motion to suppress the DNA evidence obtained. In particular, they argued that the use of whole genome sequencing in matching Heumann's DNA to the crime could not be admitted. The motion is based on the claims that the sequencing techniques are still new and have not been proven to be reliable. The hair that is alleged to connect the defendant to the crime was a rootless hair. DNA matching from rootless hair is still a fairly new concept that is still being studied, although some jurisdictions have admitted it.
What is genome sequencing:
As modern technology develops, courts are increasingly more likely to enter in evidence derived from new techniques, due to their likelihood of being backed by sound evidence that renders them reliable. The digitization of information has made it significantly easier for research to be produced, shared, and subsequently fact-checked. Vast access to information has led to great discoveries in the field of DNA. Landmark research, known as The Human Genome Project (HGP), was a 13-year project that began in 1990 that aimed to develop tools to identify genes by deciphering “...the chemical sequence of the complete human genetic material.” The project ended in 2003, but research on the topic did not. Finally, in 2022, scientists finished mapping a human genome through the Telomere-to-Telomere Consortium (T2T). This new reference genome was named T2T-CHM13 and includes gapless telomere-to-telomere mapping for all of a human's 22 autosomes and the X chromosome.
The HGP was a feat that was precisely curated with the help of many qualified experts in the field. Its accuracy is the key here, as that is one of the qualifications to admit novel scientific evidence. The project acknowledges that the reference genome fails to capture the diversity of all human genetic variation. Nevertheless, having an entire human genome mapped has been groundbreaking for research and medical discoveries, but also for courts. The mapped genome has made it possible for cold cases, such as this one, to be reopened and solved.
Admitting Novel Scientific Evidence:
These significant advances in DNA testing have opened up a whole new world of evidence in trials such as this one. To determine whether the use of whole genome sequencing was admissible in Heuermann’s case, the court entered a Frye Hearing. A Frye hearing is a legal proceeding that is used to determine whether new scientific evidence can be admitted into court. The hearing is supposed to ensure that facts are not presented to the jury without scientific backing. The main burden to surpass is whether the techniques or methodologies being used are considered “generally accepted” in the relevant scientific community. It is the proponent’s (the party bringing forth the evidence) burden to prove this. Expert witnesses from both sides will testify in the hearing, although their testimony will not be focused on their findings or conclusions. Instead, they will speak to the accuracy and legitimacy of the evidence in question.
Flaws with using the Frye standard:
In many jurisdictions, the Frye standard is no longer adhered to. Courts have held that the Frye standard is too rigid and does not allow for consideration of other factors beyond general acceptance. It has since been replaced in most other jurisdictions by the Daubert standard. This test allows for consideration of factors such as peer review, error rates, and other testing. It is considered to be the standard that fits more closely to modern analysis standards. However, New York still uses the Frye standard, hence the hearing in Heuermann’s case.
Argument Analysis:
The argument that the DNA evidence had not been generally accepted is not completely unfounded. Due to its more recent development, the argument could be made, as the defense in Heuermann’s case did, that the evidence simply had not been generally accepted. Where the defense failed to succeed was in its expert testimony. The first expert that testified, Mr. Nathaniel Adams, had a Bachelor of Science degree, and had not finished his master’s thesis. This weak expert background did not help the defense’s case, nor did the fact that Mr. Adams only reviewed the notes generated during the DNA testing. Having a more robust look into how the DNA evidence was actually tested would have been an effective way to shut down the prosecution. Instead, the defense presented an unprepared witness who testified on a number of occasions about their lack of notes on the case, and lack of preparedness in general. Their next witness, Dr. Dan Krane, happened to be Mr. Adams’ professor. Dr. Krane admitted on the stand that a witness not having a master’s degree may be problematic in this case, not only due to lack of credentials but also because of lack of sophisticated knowledge. Dr. Krane did elaborate on the prosecution's evidence and how that was not sufficient, but failed to provide significant peer-reviewed evidence to back his side. He ultimately did not prevail and was enfeebled by the prosecution when they started questioning his legitimacy. It was brought to the Court's attention that he himself had peer-reviewed articles that were rejected by journals.
The prosecution’s witnesses ultimately prevailed in showing that whole genome sequencing is generally accepted. They called three witnesses who did an excellent job in explaining the technology used in this type of DNA testing, and explained to the court why the techniques are reliable. They first called Dr. Kelley Harris, a population geneticist, professor, and genetics-related cancer researcher. She has published roughly 40 peer-reviewed articles, most having to do with whole genome sequencing. Dr. Harris was a peer-reviewer for the paper by Dr. Green on whole genome sequencing of rootless hairs, which the issue pertains to. This research is incredibly relevant as it is what was used to develop the technique in question. She explained that while DNA sequences can be similar among ancestors, it is nearly impossible to have the same exact DNA. It can happen that the technology used fails and returns a false match, but it is unlikely.
The next witness was Dr. Nicole Novroski. She works as the Associate Director of the Center for Human Identification, a globally recognized forensic research lab. Her role is to continue to develop and validate whole-genome sequencing. As part of her current work, she is evaluating Astrea Forensics, Dr. Green’s company. Dr. Novroski testified that Dr. Green’s method of DNA extraction from rootless hairs is not only effective, but generally accepted, citing peer-reviewed research on the topic. She further testified that similar evidence has been admitted in other jurisdictions, including California. California, like New York, still uses the Frye standard to admit novel evidence. Showing that jurisdictions with similar rules admit this evidence strengthened the prosecution's case immensely.
Finally, Dr. Richard Green himself testified. Among his impressive list of credentials, Dr. Green is the leading researcher on whole genome sequencing using rootless hairs. His company, Astrea, has analyzed thousands of DNA samples for law enforcement, and has even analyzed for other labs. Dr. Green testified about his software that he developed to match DNA, and further explained how he tested it. He would input two samples he knew were the same, or two that he knew were different, to ensure that there were no false positives or negatives occurring. Dr. Green also would create issues to test the computer program, which he found had no impact on the program.
Overall, the prosecution did a more thorough evaluation of the technique. They provided many peer-reviewed articles, broke down their argument, and presented their experts so that the testimony would build from one expert to the next, all pointing at Dr. Green’s culminating testimony. The defense relied on two comparatively less qualified experts, both of whom were undermined during their cross-examinations. There was not much testimony as to why whole genome sequencing is not generally accepted, and the evidence that they did provide for it was weak and not reflected by peer-reviewed research.
Courts Ruling:
The court held that the standard of general acceptance in the relevant scientific community had been met. The DNA evidence being offered was already being used in other jurisdictions, and the prosecution met their burden.
Karen Czapkowski is a junior majoring in political science and economics.
Sources
Canty, M. & Tokhi, S. (April 13, 2025). Long Island serial killings: A timeline of the investigation. CBS News. https://www.cbsnews.com/news/long-island-serial-killings-investigation-timeline-48-hours/
Collins, F. S., & Fink, L. (1995). The Human Genome Project. Alcohol health and research world, 19(3), 190–195. https://pmc.ncbi.nlm.nih.gov/articles/PMC6875757/
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)
Frye v. United States, 293 F. 1013 (D.C. Cir. 1923)
Hatcliffe, J. (2025). The Gilgo Beach Murders – The Defense’s Attempt to Preclude DNA Evidence. Haub Advocacy Blogs. https://haubadvocacy.blogs.pace.edu/2025/03/31/the-gilgo-beach-murders-the-defenses-attempt-to-preclude-dna-evidence/
Nurk, S., Koren, S., Rhie, A., Rautiainen, M., Bzikadze, A. V., Mikheenko, A., Vollger, M. R., Altemose, N., Uralsky, L., Gershman, A., Aganezov, S., Hoyt, S. J., Diekhans, M., Logsdon, G. A., Alonge, M., Antonarakis, S. E., Borchers, M., Bouffard, G. G., Brooks, S. Y., Caldas, G. V., … Phillippy, A. M. (2022). The complete sequence of a human genome. Science (New York, N.Y.), 376(6588), 44–53. https://doi.org/10.1126/science.abj6987
People v. Heuermann, 2025 NY Slip Op 25203
