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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The search for answers began in 1994 when a fisherman discovered a body in the lake. The Snohomish County Medical Examiner's office determined the deceased to be between 25 and 35 years old and the victim of a violent homicide. Multiple varied facial reconstructions were made for the victim over the years, in part because ethnicity assessment was inconclusive. Each artistic rendition was shared with the public in hopes that someone would recognize the victim and come forward with information.
Detective Scharf and Investigator Jorgensen reached out to Othram to perform DNA testing. Despite having less than a fifth of a nanogram (less than 20 cell’s worth) of badly degraded and heavily contaminated human DNA to work with (a scenario currently inaccessible by any other forensic lab), Othram’s scientists were able to reconstruct a genealogical profile.
After uploading the genealogical profile to a public genealogical database, a match was identified, allowing Othram’s internal laboratory team and investigators to establish an identification: Rodney Johnson.
Usually, one match is not enough to point to a single person. However, this match had included another clue in their public database profile. They belonged to a distinctive direct maternal lineage. The high-resolution profile developed by Othram allowed investigators to perfectly match up this uncommon maternal lineage signature.
The investigators then found a record for a missing person that appeared to match Mr. Johnson. Interestingly, although the missing person was reported in 1996, the Mr. Johnson had last been seen in 1987. He was only 25 years old. It’s likely that the Lake Stickney John Doe had been in the lake for as many as seven years before being discovered.
Investigators reached out to next-of-kin and used legacy DNA testing to confirm the identity established from the genealogical profile. Investigators are now working to better understand what might have happened in the days leading up the Johnson’s death.