- It is probably one of the more powerful tools we can think of, says Ricky Ansell, operations expert at the National Forensic Center, NFC, in Linköping.
The investigation into the double murder in Linköping in 2004 had not succeeded in finding any perpetrator, despite the fact that there were DNA traces.
It was only after DNA and genealogy were combined that the murder mystery was solved.
The double murder served as a pilot project
The working method was new for the Swedish police and the investigation into the double murder in Linköping was allowed to function as a pilot project.
A report on the project has now been presented and the authors come to the conclusion that it would be appropriate for the Swedish police to continue working in this way.
- The most important thing we have come to is that the method works, says Ricky Ansell.
Some things need to be adjusted and investigated more, but the goal is for this way of working to become another tool for the police.
There must be enough DNA
However, this is not a magic wand that solves all old crimes.
Several criteria must be met.
First and foremost, there must be enough DNA to work with.
The genealogical databases used in the double murder investigation need more data from the DNA trace than was needed in the investigations that have been common so far.
Another thing that affects is that there must be useful DNA to compare with in the databases.
The genealogy databases are far from data from an entire population.
If there is too little information in the DNA trace from a crime scene, a police investigation can even be led in the wrong direction.
At one point in the double murder investigation, a connection to Germany emerged, which then turned out to be incorrect.