A man is suspected of having raped a woman in a cabin on a Finland ferry during the night towards Sunday.
The cabin has been cordoned off for technical examination.
The suspect was apprehended by staff on board the ferry and the Police took over the arrest when it arrived at the Stockholm harbour.
Both the suspect and the plaintiff are adult individuals, says the Police's press spokesperson Carina Skagerlind.
A preliminary investigation regarding rape and assault has been initiated.
