Police Deploy Genetic Genealogy to Solve Cold Cases in Sweden

Swedish law enforcement has now fully implemented genetic genealogy as a tool in criminal investigations, strengthening efforts to resolve both recent and long-standing unsolved cases. This advanced method, which originated in the United States, was first trialed in Sweden in 2020 and contributed to identifying the perpetrator in a high-profile double homicide in Linköping that occurred in 2004.

Since July, the police have had legal authorization to apply this investigative technique more broadly, spanning both current and historic cases. The National Forensic Centre (NFC) has expanded its workforce to include specialists in genealogical research, aiming to handle several cases simultaneously across different stages of investigation. While the process is ongoing, no successful matches have been reported so far.

Initiating an investigation using genetic genealogy requires a prosecutor's decision, and in the case of cold cases, a preliminary investigation must be reopened. The method is only considered when traditional investigative avenues have been exhausted and there is a high probability that the DNA evidence originates from the suspect. The selection process for suitable cases places significant emphasis on the likelihood of the DNA link resolving the crime, with prosecutorial assessment of the evidence playing a central role.

Before genealogical research can begin, an advanced DNA analysis is necessary, which can take several months. The timeframe for identifying potential suspects varies widely and depends on the quality of the DNA sample and the presence of relevant matches in genealogical databases. In some instances, results can emerge within a week, while in others, it may take years or remain unresolved if no meaningful matches are found.

Among the cases under consideration are the double homicide in Brattås from 2005, where DNA evidence was recovered at the crime scene, and the 2001 murder of a 28-year-old woman in Helsingborg, which also contains DNA traces from an unidentified individual. Authorities have indicated that the application of genetic genealogy is not limited to homicide cases; it may also be used in the investigation of severe sexual offenses. The rationale is that active offenders could still pose a threat, and resolving these cases may prevent future crimes.

The introduction of genetic genealogy marks a significant development in Swedish forensic investigations, providing law enforcement with a powerful resource to revisit unresolved crimes and potentially bring long-awaited closure to victims' families. The method's effectiveness will depend on a combination of robust DNA evidence, comprehensive genealogical databases, and the ongoing collaboration between forensic experts and legal authorities.