Lindsay Clancy Trial: The DNA Analyst Testifies Only Her DNA Was on the Outside Wall of the House

A Massachusetts State Police DNA analyst spent almost her whole testimony explaining why the DNA on the exercise bands proved so little, and then delivered one finding that was not tangled at all. This is the Lindsay Clancy trial, the case most people know as the Duxbury Mom trial. Lindsay Clancy is charged in the deaths of her three children, Cora, Dawson, and Callan, at the family home in Duxbury, Massachusetts. The Commonwealth says she planned it. The defense says her mind was lost to postpartum psychosis that no one stopped. She is presumed innocent, and it is the Commonwealth that has to prove she was criminally responsible. Katarina Stashyn processed and interpreted the DNA in this case for the state crime lab. She did the work herself and defends it under cross, which is why her full testimony is worth watching instead of a few minutes of it. Most of what she touched came back complicated. Two parents and three children share so much DNA that on the exercise bands recovered from the scene she had to run the same sample two different ways and warn the jury that the results cancel each other out. If one child is in a mixture, another cannot be. She is blunt about the limits: when a profile looks like five or more people, the lab's own rules say the work stops. At one point the defense loses patience with the math out loud, telling the judge this is typical DNA gobbledygook. The objection is overruled. Then the picture changes. On the outside of the house, a single stain on the back wall comes back to one person. The lab puts the likelihood at 18 octillion times more likely if that DNA came from Lindsay Clancy than from an unknown, unrelated person, and every other member of the family is excluded. A second exterior stain says the same thing at 96 trillion. After twenty-plus minutes of numbers that cancel, two that do not. One thing to keep straight, because Stashyn is careful about it herself. A likelihood ratio is not the odds that a profile belongs to a person, and it is not a statement about how the DNA got there. It is a measure of how much more the evidence supports including someone than excluding them. She corrects that point on the record when the defense tries to turn a big number into a rarity statistic. What the exterior stains support is that Lindsay Clancy is included and the rest of the family is not. What they do not do is tell you how it happened. That part is for the jury. For both sides there is something here. The defense can lean on the tangled bands and the false-exclusion problem to argue the physical evidence is messier than it sounds. The state can point to the outside wall, where the DNA is clean and it is hers. This is her complete testimony, the recesses removed, so you can follow the whole chain from the first mixture to the last exterior stain. KEY MOMENTS 3:30 - She walks the jury through the four-step lab process and the contamination controls 8:50 - The yellow exercise band comes back a tangle of shared family DNA 13:37 - The defense objects out loud, calling the science gobbledygook 13:57 - She corrects the record on what a likelihood ratio does and does not mean 24:37 - A stain on the outside wall of the house comes back to Lindsay Clancy alone COMPLETE CASE COVERAGE justiceisaprocess.com SUBSCRIBE for daily trial coverage. CASE BACKGROUND REPORT: https://justiceisaprocess.com/ma-v-cl... Complete case overview: the charges, the timeline, the people at the center, the McHoul standard, and the legal analysis behind Commonwealth of Massachusetts v. Lindsay Clancy. PLAYLISTS AND RESOURCES Website: https://justiceisaprocess.com/coverag... Full Trial Live Broadcasts:    • Commonwealth v. Lindsay Clancy: Full Trial...   No Breaks Edition:    • Commonwealth v. Lindsay Clancy: No Breaks ...   Trial Analysis Podcast:    • Commonwealth v. Lindsay Clancy: Case Story...   Key Moments and Testimony:    • Commonwealth v. Lindsay Clancy: Key Moment...   Subscribe for Daily Coverage:    / @justiceisaprocess   FAIR USE AND EDUCATIONAL PURPOSE This content is produced under Fair Use (17 U.S.C. 107) for news reporting, criticism, and educational purposes. We provide transformative commentary on public court proceedings, advancing public understanding of the judicial process through timestamps, analysis, and educational context. #JusticeIsAProcess #DuxburyMomTrial #LindsayClancy