Kim Wall's boyfriend alerted police when the reporter didn't arrive home, after boarding the ship for what was supposed to be just a few hours, at around 7pm on Thursday 10th August.
However, the sub's owner Peter Madsen claimed he dropped the journalist back to shore around 10:30pm that night.
A large-scale search was unable to find any trace of the missing woman, and Madsen was subsequently charged with her manslaughter.
The 46-year-old then told authorities Wall had died in an accident which occurred on board the submarine and that he had "buried her at sea at an unspecified location," a police statement said.
Now, a woman's headless body has been found washed ashore in Copenhagen, but police are saying it's too early to tell whether it is Kim Wall, BBC reports.
The body, which was also missing its legs and arms, has been sent for forensic testing.