MA v Lindsay Clancy - Katarina Stashyn - Forensic Scientist - DNA Unit - Mass State Police

Testimony of DNA Analyst Katarina Stashyn, on day 7 of the Lindsay Clancy trial: Witness Background and Qualifications • Current Role: Currently employed as a criminalist in the biology and forensic investigation sections of the Washoe County Sheriff's Office Forensic Science Division in Reno, Nevada. • Education: She holds both a bachelor's and master's degree in biotechnology from the University of Nevada, Reno. • Prior Experience: From June 2021 to February 2025, she worked as a forensic scientist in the DNA unit of the Massachusetts State Police Crime Laboratory. • Professional Competency: She has successfully passed all professional competency and proficiency tests throughout her career. DNA Science and Testing Methodology • DNA Fundamentals: DNA (deoxyribonucleic acid) is genetic information stored in our cells, inherited approximately half from each parent. Forensically, no two individuals are expected to share the same DNA profile, which remains identical across all cell types in a person's body (barring mutations). The Four-Step Analysis Process: • Extraction: Heat and chemicals are applied to break open cells, isolating and releasing the DNA. • Quantification: Analysts determine a reliable estimate of the DNA quantity to optimize the remainder of the testing process. • Amplification: Millions of copies of specific DNA areas are generated to make them detectable and visualizable. • Detection: The millions of generated copies are separated and visualized, yielding a DNA profile for review and interpretation. Quality Controls and Peer Review: • Positive Controls: A sample containing a known DNA profile is run alongside the evidence to confirm the laboratory process is working. • Negative Controls: A sample with no DNA is processed alongside the evidence to monitor for contamination and ensure clean laboratory techniques. • Double-Review Process: Every case goes through technical review (another analyst checks the protocol adherence and conclusions) and administrative review (clerical accuracy and completeness checks). Stashyn’s work in this case followed all protocols, had acceptable controls, and passed both review stages. DNA Findings: Yellow Exercise Band Stashyn did not handle the physical exercise bands; instead, she processed swabs taken from them. Swabs from the Ends (Item 2-2.1.1): • The sample yielded a DNA mixture including male DNA. • Assuming 2 contributors: The DNA profile is at least 1.7 nonillion times more likely if it originated from Dawson Clancy and an unknown individual than if it originated from two unknown unrelated individuals. Dawson is included; Cora, Callan, Patrick, and Lindsay Clancy are excluded. • Both interpretations show high inclusionary statistics for Dawson Clancy. Swabs from the Middle (Item 2-2.2.1): • The profile was interpreted as a mixture of two contributors, including male DNA. • Dawson Clancy: Included with a likelihood ratio of 1.5 nonillion. • Patrick Clancy: Included with a likelihood ratio of 1.4 billion. • Callan Clancy: Included with a likelihood ratio of 3.6 million. • Cora and Lindsay Clancy: Both are excluded. DNA Findings: Black Exercise Band Swabs from the Ends (Item 2-3.1.1): • The sample was a mixture containing male DNA but was deemed not suitable for comparison. Swabs from the Middle (Item 2-3.2.1): • The profile was interpreted as a mixture of three contributors, including male DNA. • Cora Clancy: Included with the highest likelihood ratio of 1.69 million. • Dawson Clancy: Included with a likelihood ratio of 870 trillion. • Patrick Clancy: Included with a likelihood ratio of 220,000. • Callan Clancy: Included with a likelihood ratio of 2,600. • Lindsay Clancy: Included with a limited likelihood ratio of 11. DNA Findings: Backside of House (Shingles at 47 Summer Street) Stashyn analyzed swabs taken from shingles on the backside of the home: Item 14-1 (Stain B): • Yielded a single-contributor female DNA profile (not a mixture). • The profile is at least 18 octillion times more likely if it originated from Lindsay Clancy than from an unknown unrelated individual, supporting her inclusion. All other family members are excluded. Item 14-2 (Stain C): • The profile was a mixture but not suitable for comparison due to its low-level quality and a lack of sufficient information for interpretation. Item 14-3 (Stain D): • Yielded a single-contributor female DNA profile. Lindsay Clancy Trial Playlist:    • MA v Lindsay Clancy - Jury Selection Day 1