The Swedish double murder mystery was solved using DNA-based genealogy, of a murder committed 16 years ago.
On October 19th, 2004, an 8-year-old boy travelling from his home to school in the town of Linköping in southern Sweden was murdered. What’s more, a 56-year-old woman who witnessed the crime was also murdered by the assailant on the same day. However, the identity of the assailant remained a mystery till 16 years later. The case, however, was eventually solved using DNA-based genealogy.
During investigations, the police found a cap and knife at the crime scene that were used to murder the victims. And although, there were traces of DNA on the murder weapon, the detectives were unable to trace the murderer.
In 2018, the Swedish police became aware of the arrest of “Golden State Killer”, Joseph James DeAngelo using using genetic information from the commercial genealogy website GEDmatch. In this notorious case, the police used DNA from the crime scene and DNA of people who voluntarily submitted their gene information to public genealogy databases for tracing their family tree. Through this the police were able to identify several of Joseph James DeAngelo’s family members, which led to the murderer himself. The method proved to be remarkably successful to trace down a murderer.
After learning about the success of the technology, the Swedish police asked the authorities whether they could solve the they could solve the Linköping murders, using this method.
The investigators were able to find a number of distant relatives of the assailant through the DNA found at the crime scene, on the platforms GEDmatch and FamilyTree. A further investigation helped identify two prime suspects. Further investigation revealed that one of the two suspects was a direct match to the DNA found at the crime scene.
According to local media reports, the murderers name was Daniel Nyqvist, a Swedish man who killed the victims while “under the influence of a severe psychological disorder.”
The man went for trial in 2020 and was charged for the crime.
While the method is increasingly being used by authorities, it’s full of legal and ethical dilemmas. “We want to tell others about the problems that we faced when working with this pilot case, and how we dealt with them. We can prevent others reinventing the wheel, and make sure that the knowledge available is extended and improved”, Andreas Tillmar, lead study author and adjunct senior lecturer in forensic genetics at the Department of Biomedical and Clinical Sciences at Linköping University, said in a statement.
References
Getting the conclusive lead with investigative genetic genealogy – A successful case study of a 16 year old double murder in Sweden https://www.fsigenetics.com/article/S1872-4973(21)00063-6/fulltext#secsect0020
