The woman was found by a maid in a first floor room. The maid first thought the woman was asleep, thelocal.se said.
"We can confirm that it is a woman whom we believe was slain and we have therefore launched a preliminary investigation into murder or manslaughter," police spokesman Lars Bystrom told news agency TT.
Police have asked hotel patrons to come forward with any information they might have.
Notable deaths of 2014 [PHOTOS]