Las Vegas police solve an old murder case using record-low volume of DNA

Las Vegas police appear to have broken a record using parentage to find suspects in the cold case, BBC News reports that Vegas law enforcement alleges the 1989 murder of 14-year-old Stephanie Isaacson (pictured here ) with the smallest known amount of DNA. Investigators sent just 0.12 nanograms of DNA samples, or about 15 cells, to Othram’s gene sequencing lab to find a match. For context, a typical home DNA test kit collects at least 750 nanograms.

Othram used the sequences to search ancestral databases, locate the suspect’s cousin, and identify Darren Roy Marchand as the perpetrator. The team confirmed the match by comparing the sample to Marchand’s DNA from an arrest for a 1986 murder. Marchand was never convicted and died in 1995.

Vegas Police opened the investigation after Resident Justin Woo donated money to help law enforcement agencies resolve cases with “minimal” DNA scores. The investigation into Othram began on January 19, but it wasn’t until July 12 that the company identified a suspect.

Othram boss David Mittlemen described the efforts in a discussion with the BBC as a “huge milestone”. This could theoretically solve cold cases where the samples were previously thought to be too small to be usable.

However, the breakthrough won’t necessarily delight everyone. There have been concerns that law enforcement authorities may conduct these tests, and the Department of Justice has guidelines in place to prevent precisely this type of abuse. While there is no evidence that the Vegas authorities crossed borders in the Richardson case, a much wider range of potentially solvable cases also increases the potential for further data breaches.