Police in Denmark say that Swedish volunteers looking for leads in the search for a missing Swedish woman who was on an amateur-built submarine the night before it sank off Copenhagen have found "parts of a life jacket" but say it's probably not related to the case.

Emma Forseth, spokeswoman for the private Swedish Sea Rescue Society, said Wednesday that the objects were found late Tuesday on the Danish side of the Oresund strait where they were taking part "in a drill" with the Danish Sea Rescue Society.

Submarine owner Peter Madsen was questioned after the UC3 Nautilus sank Friday. Police later arrested the Dane on preliminary manslaughter charges in the disappearance of 30-year-old freelance journalist Kim Wall. He has denied having anything to do with her vanishing.