“There are clear signs that make us suspect that someone has ended the man’s life,” Gothenburg police spokesman Christer Fuxborg told Swedish news agency TT.
The man was found by passersby on a walkway near the Röda Sten Art Centre on Sunday morning.
According to police sources, there was a party in this area of Klippan on Saturday night, although it remains unclear whether the man attended.
“It is of high priority that we speak to anyone who spent the evening or night with him.
“We need to find out if he was at the party or if he was in the area for another purpose.”
Initial forensic investigations seem to offer some clues into the case although police do not wish to disclose their findings yet.
There are no suspects at present, TT reported.
The police are interested in speaking to anyone who was in either in Älvsborgsbron or Klippan on Saturday night and may have noticed any suspicious behaviour.
The man was identified by relatives on Sunday morning. He was a Gothenburg resident.