On their website, the police write that since November last year, there have been "a number of cases" of break-ins into estates of deceased persons in the eastern and middle police regions.
Primarily, it is Sörmland County that has been affected, but also the area around Jönköping.
The police do not want to disclose the exact number of cases.
"What we can see is that the connection is that it is precisely the estates of deceased persons that have been targeted. We are working across regional boundaries to make progress in the investigations, since we believe it may involve the same perpetrators," says Helena Wahlund, analyst at the police, on the authority's website.
According to Wahlund, the same modus operandi has been used in the different break-ins. However, it is unclear whether it is the same perpetrators.