People v. Heuermann

2025 NY Slip Op 25203
CourtNew York Supreme Court, Suffolk County
DecidedSeptember 3, 2025
DocketCase No. 73544-24
StatusPublished

This text of 2025 NY Slip Op 25203 (People v. Heuermann) is published on Counsel Stack Legal Research, covering New York Supreme Court, Suffolk County primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
People v. Heuermann, 2025 NY Slip Op 25203 (N.Y. Super. Ct. 2025).

Opinion

People v Heuermann (2025 NY Slip Op 25203) [*1]

People v Heuermann
2025 NY Slip Op 25203
Decided on September 3, 2025
Supreme Court, Suffolk County
Mazzei, J.
Published by New York State Law Reporting Bureau pursuant to Judiciary Law § 431.
This opinion is uncorrected and subject to revision before publication in the printed Official Reports.


Decided on September 3, 2025
Supreme Court, Suffolk County


The People of the State of New York,

against

Rex A. Heuermann, Defendant.




Case No. 73544-24

HON. RAYMOND A. TIERNEY
District Attorney, Suffolk County
ADA Nicholas Santomartino
ADA Andrew Lee
ADA Lawrence Opisso
200 Center Drive
Riverhead, NY 11901

MICHAEL BROWN, ESQ.
DANIELLE COYSH, ESQ.
Attorneys for Defendant
320 Carleton Avenue, Suite 2000
Central Islip, NY 11722
Timothy P. Mazzei, J.

On March 28, 2025, April 2, 2025, April 3, 2025, April 15, 2025, April 16, 2025, April 17, 2025, June 17, 2025, June 18, 2025, and July 17, 2025, a hearing was conducted by the Court pursuant to Frye v United States, 293 F 1013 (DC Cir. 1923) as to the admissibility of nuclear DNA results as well as any expert testimony pertaining to said nuclear DNA results obtained from rootless hairs recovered from the person and/or crime scene of Maureen Brainard Barnes, Megan Waterman, Amber Costello, Sandra Costilla, Jessica Taylor and Valerie Mack

Findings of Fact

The People's Witnesses

Dr. Kelley Harris

Dr. Harris testified that she is a Population Geneticist and has been an Associate Professor of Genome Sciences at the University of Washington since 2018. Dr. Harris also holds a position at the Fred Hutchinson Cancer Research Center where she gives research updates and [*2]exchanges ideas in computational biology. She has also published 40 peer-reviewed articles with most of them concentrating on whole genome sequencing, the process by which you obtain DNA from everywhere across the whole genome and analyze all or most of it. After receiving her Bachelor's Degree from Harvard University, Dr. Harris went on to receive her Master's Degree in biological science from Cambridge University's Genomic Center. Her Master's Degree thesis involved calculating the reliability of genetic identity over a stretch of the genome when you can assume that all of the sites of the genome you observe are likely the same because of recent ancestry. This is extremely helpful when the sample collected only contains a small amount of DNA and statistical analysis is used to check the reliability. Dr. Harris used the 1,000 Genomes Project in her research which is a reference panel containing sets of genomes from 2,504 different individuals around the world. It represents the genetic variation found in the entire population of the world and is publicly available for use. It has been used to calculate statistics for population genetics. In her testimony, Dr. Harris referred to a peer-reviewed article regarding the 1,000 Genome Project (People's 1E). After receiving her Master's Degree, Dr. Harris earned her doctorate in applied mathematics with an emphasis in computational biology from the University of California at Berkeley. During her studies, she used ratios to calculate how likely some observations were that she made under different scenarios to confirm or disprove her hypotheses. Dr. Harris then went on to complete a post-doctorate fellowship at Stanford University in their Department of Genetics. Dr. Harris further testified that she also has experience in bioinformatics, the process by which you have a small amount of DNA, place it through a DNA sequencer, receive an output of pieces of DNA, and then stitch it together so that the DNA is interpretable. A sequencer is a device which DNA is placed into that has been library prepped, and after being run through the machine, generates the sequence of all of the fragments of DNA that were placed into the sequencer. The Illumina sequencer is the dominant technology on the market and has been generally accepted by the scientific community to develop a DNA profile. Dr. Harris noted that she is not an expert in forensic science.

DNA contains four bases: adenine (A), cytosine (c), thymine (T) and guanine (G). Each individual has two copies of their nuclear DNA-one from their mother and one from their father. Each individual also can have hundreds or thousands of mitochondrial DNA depending on what type of cell in which it is located. Mitochondrial DNA is inherited by the individual from their mother. A short tandem repeat (STR) is when one, two, or three of the four of the bases of DNA (ACTG) repeat themselves in the genome. For example, if ACT or ACG or ATG, etc. were repeated several times when looking at the DNA in a genome. STRs have been used in forensic science since the 1980s. Whole genome sequencing focuses on these repeats after obtaining DNA from across the entire genome. The whole genome will often become amplified into multiple copies which then get cut up into pieces. The pieces are then placed into a genome sequencer and read out as a string of ACTGs by stitching them back together. Sometimes there are gaps in the string. Dr. Harris testified that whole genome sequencing can be used to create a nuclear DNA profile, and this has been generally accepted in the scientific community.

SNP (single nucleotide polymorphism) DNA refers to one base in the genome where a variation has been observed. SNP DNA is used in medical genetics, forensic identification, etc.According to Dr. Harris, the best method to develop a DNA profile when you are dealing with a short fragment of DNA is whole genome sequencing. In addition, Dr. Harris testified that [*3]using a computer program to calculate a likelihood ratio of the statistical significance in whole genome sequencing DNA profiles is widely accepted in the scientific community.

Dr. Harris peer-reviewed Dr. Richard Green's paper entitled, "A Computational Approach for Positive Genetic Identification and Relatedness Detection From Low-Coverage Shotgun Sequencing Data." (Defendant's B). This paper discussed whole genome sequencing of rootless hairs as compared to a higher quality DNA sample taken from a lab including the use of a computer software entitled IBDGem, created by Dr. Green, which calculated the likelihood ratio, and found that his system was reliable. She based this opinion upon her review of Dr. Green's paper, the study he performed, and his results. She noted that she co-authored peer-reviewed articles with both Dr. Green and his wife, Dr. Beth Shapiro. Dr. Harris explained that IBDGem uses the 1,000 Genomes Project as a reference sample. IBDGem examines hundreds of SNP locations at a time in a window and then combines information across millions of SNP locations genome-wide. Dr. Harris explained a test where IBDGem was used to compare a hair sample to the saliva of the person whom the hair sample came from as well as another test where IBDGem was used to compare a hair sample from an individual with the saliva of a different individual who did not give the hair sample. The likelihood ratio for the first test (the hair sample and saliva sample from the same individual) was up to 200 times more likely that the hair and saliva came from the same individual.

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Bluebook (online)
2025 NY Slip Op 25203, Counsel Stack Legal Research, https://law.counselstack.com/opinion/people-v-heuermann-nysuprctfflk-2025.