The mystery of 16-year-old double murder in Sweden was solved last year using data from genealogy websites, a method first used to identify and capture the “Golden State Killer” in 2018. Detailing the case in a new study, scientists in Sweden say it’s the first time this technology has been used to catch a murderer outside the US.
On October 19, 2004, an eight-year-old boy was stabbed to death while walking to school in the city of Linköping in southern Sweden. The attacker then turned on a 56-year-old woman who had just left her home and witnessed the event, stabbing her several times and leaving her for dead. The attacker fled the scene but left behind a knitted cap and the butterfly knife he used to kill the victims. Although traces of the murder’s DNA had been traced on the weapon, detectives ran out of leads and the investigation dried up.
Swedish police then became aware of the arrest of Joseph James DeAngelo – the so-called “Golden State Killer” – using genetic information from the commercial genealogy website GEDmatch. In this notorious case, police compared genetic material left at the crime scene to the DNA of people who voluntarily submitted their gene information to public genealogy databases to trace their own family tree. This was able to identify a number of DeAngelo’s family members, eventually leading them to DeAngelo himself. After following the suspect, they then picked up an unidentified object he discarded to obtain his DNA, which then linked him to a number of the crimes. The novel method proved to be a remarkable success; DeAngelo will spend the rest of his life behind bars.
Intrigued by the story, Swedish police asked higher authorities whether they could solve the Linköping murders using this DNA-based genealogy method in a pilot study. They eventually got the green light in 2019, and a new investigation got underway.
Sifting through data on the platforms GEDmatch and FamilyTree, investigators found a number of distant relatives to the DNA picked up from the crime scene. A further investigation used this lead to identify two prime suspects: two brothers. More snooping revealed one of the brothers had a direct match to the crime scene DNA, affirming his guilt.
You can read all the details in an article at https://www.fsigenetics.com/article/S1872-4973(21)00063-6/fulltext