For years, victims were listed on cold case files in law enforcement evidence boxes. While never forgotten, limitations in forensic science prevented their cases from being closed. Families waited decades for answers and justice while their killers remained unidentified.
In 2018, a new tool for crime solving rose to prominence as the notorious Golden State Killer was finally unmasked; forensic genetic genealogy. To begin, investigators upload their unknown DNA profile to the site, which generates a list of the closest genetic matches, based on how many centimorgans (cM) of DNA are shared with the unknown person. Next, investigators will begin to build back the unknown person's family tree until a common ancestor is uncovered. Then, they will build the family trees forward, identifying every descendent possible, using traditional genealogy techniques. Once the trees have been fully built out, investigators look to identify candidate persons that might match the unknown person. Once a person of interest has been identified, new DNA can be collected to compare to the original forensic sample.
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Advanced DNA testing has revealed Darren Roy Marchand as the suspected perpetrator in the brutal murder of 14-year-old Stephanie Isaacson from Las Vegas.
In June 1989, 14-year-old Stephanie Isaacson headed out on her morning walk to Eldorado High School. The Las Vegas teenager frequently took a shortcut through a vacant sandlot off Steward Avenue and Linn Lane to get to school quicker. After school let out that afternoon, Stephanie’s father began to worry when she did not arrive home at her usual time. Upon calling the school in hopes of finding out where she may be, it was revealed that Stephanie never made it to school.
A missing person report was filed and law enforcement investigators then conducted a local search, canvassing the area around the typical route that Stephanie would take to school. Her body was found at a sandlot and investigators determined she had been sexually assaulted and strangled to death. A lengthy investigation, spanning decades, ensued and all available investigative leads were exhausted. Stephanie's killer remained undiscovered.
In 2021, the Las Vegas Metropolitan Police Department teamed up with Othram to reexamine DNA evidence from the crime scene in hopes that advanced DNA testing might generate new leads in the investigation. Funding assistance was generously provided by Justin Woo, founder of the non-profit organization Vegas Helps.
Othram scientists used Forensic-Grade Genome Sequencing® to build a genealogical profile from the remaining DNA evidence — only 120 picograms (or 0.12 nanograms) of DNA. This sets a new lower limit on the quantity of DNA required to build a genealogical profile for a suspect of a crime.
The Othram genealogy team used the profile to develop investigative leads that were returned to LVMPD. Detectives were able to confirm the identity of the suspect in Stephanie's sexual assault and murder as Darren Roy Marchand. The suspect died in 1995 by suicide but has been tied to other crimes.