It was at the end of September that Valdemarsvik Municipality decided to close its schools - after threats were directed at school children. Now the police have found traces of the perpetrator. According to Norrköping's newspapers, it must be DNA or fingerprints found on the threat letters sent to various places in Valdemarsvik.

- In total, there are four similar threat letters that have come to the municipality. But right now, we have no suspected person for the threats, says Christina Edevärn, who is the lead investigator for the newspaper.

Police classify the incident as grossly unlawful threat to group.

SVT News East has sought Christina Edevärn.