Innovative DNA method leads to conviction in decades-old murder case, paves way for solving more unsolved crimes in Denmark

Murderers who have thus far evaded justice could be held accountable for their crimes with new DNA methods. This comment came from the special prosecutor with the Copenhagen Police, following the conviction and sentencing of 54-year-old Henrik Krogh Rasmussen to 11 years and six months in prison for the murder of Hanne With on New Year’s Eve 1990.

For the first time in Denmark, a perpetrator has been convicted thanks to a new DNA method known as familial searching. “We must acknowledge that the police’s new investigation methods make sense. The point is that they continue the work they have already started, and hopefully there are more unidentified murderers out there who will be held accountable for what they have committed,” said special prosecutor Søren Harbo following the ruling in the Copenhagen City Court.

On the island of Bornholm, police are already using the method to investigate an unsolved murder from 1997. The victim, Connie Birgitte Svendsen from Rønne, was last seen alive on the evening of August 31, 1997, after a night out with friends. The police believe she was assaulted, beaten, and strangled. She was found dead in her bed by her employer, who was surprised that she didn’t show up for work the next day. The police found DNA on some cigarette butts and created a full DNA profile. Despite reopening the case several times, the perpetrator has not been found.

In the Hanne With case, a DNA trace was taken from the trousers and searched against the police DNA register. The register revealed DNA from Henrik Krogh Rasmussen’s son. This DNA trace is what allowed him to be brought before a judge. The ruling has been issued in the city court, and Rasmussen has requested time to consider whether he will appeal to the High Court.

The new method allows the police to search for close relatives within the register, which holds DNA samples from people who have either been convicted or charged with a crime that could result in more than one and a half years imprisonment within the last ten years. The innovation is that the DNA match no longer needs to be one-to-one, but can also be detected if, for example, one’s brother or sister appears in the police register.

Thomas Elsgaard, a police commissioner from Bornholm, has no doubt that the new method will result in more cases being solved. “This method will, of course, solve more murder cases and other serious crimes. I doubt we will solve all, but based on the familial searching, we will find more perpetrators,” he says. However, he emphasizes that the method is reserved for serious crimes, as it is very resource-intensive.

Frederik Torp Petersen, a forensic geneticist at the University of Copenhagen, also believes the method gives the police new opportunities. He explains the method is as safe as the DNA methods currently used in court cases. He also believes this won’t be the last time we see this method used. “The crucial point is whether it will also yield results. There must be a trace suitable for searching, and the perpetrator must have a close relative in the register. These two things must be met before there is a gain,” he says.

Justice Minister Peter Hummelgaard expects to propose a bill before the end of 2024 that will allow the police to also use genetic genealogy in the investigation of certain cases. Genetic genealogy is a more advanced DNA investigation method than familial searching. It can incorporate commercial DNA databases, which are currently not used by Danish police.