A 57-year-old man has been charged with rape and attempted murder in connection with a 25-year-old cold case from Bøtø on Falster. The arrest was made possible through DNA traces and kinship searching.

The suspect has been in custody since December of last year. The case involves an attack on an 11-year-old girl.

Kinship searching, a technique used in this case, involves analyzing DNA samples from crime scenes and comparing them not only to profiles in criminal databases but also to profiles of individuals who may be related to the potential perpetrator. This method broadens the scope of investigation, allowing authorities to identify suspects through familial connections.

DNA analysis plays a crucial role in modern criminal investigations. All human cells contain DNA, which forms the genetic material. Technologies analyzing DNA molecules can identify individuals for evidentiary purposes.

Traditional DNA profiling involves comparing a DNA profile extracted from a trace at a crime scene (such as saliva, blood, or hair) with a suspect’s profile or searching central DNA registers. These registers contain profiles from individuals charged in criminal cases and profiles from traces found at crime scenes. Forensic geneticists compare these profiles to either exclude a match or determine the probability that the trace was deposited by the same person. A high degree of match indicates a strong likelihood that the suspect deposited the trace. In the most conclusive matches, geneticists determine it is over a million times more probable that the suspect, rather than a random person in the Danish population, left the trace.

Kinship searching expands on this process by considering whether the trace could have been deposited by someone related to an individual in the DNA register.

This approach differs from DNA-based genealogy, which involves cooperation with commercial genealogy databases, a method not currently employed under Danish law.

The Bøtø case is not the first instance where kinship searching has led to a potential perpetrator. It was previously used in the case of the murder of Hanne With in 1990, where a 54-year-old man was sentenced to prison.

Besides kinship searching, police have utilized other advanced DNA methods, including y-chromosomal DNA analysis, which focuses on DNA found in the male sex chromosome. This method was used in the Korsør case and in the case of the murder of seven-year-old Roujan Ismaeel in 1995. Though police considered the Roujan case solved, the perpetrator had already died.