The family of a Swedish journalist missing since a trip off Copenhagen aboard a home-built submarine said they fear “the worst has happened”.

The parents and brother of 30-year-old Kim Wall said “there is nothing we wish more” than to have her back alive, but added that the chances of this are “extremely small”.

Kim WallSwedish journalist Kim Wall has been missing since last week (Tom Wall via AP)

The family told The Associated Press in an email that Ms Wall had worked in many dangerous places as a journalist, but it was unimaginable that “something could happen … just a few miles from the childhood home”.

Danish submarine owner Peter Madsen is being held on preliminary manslaughter charges over her Ms Wall’s disappearance after she went on a trip with him on his UC3 Nautilus sub, before it sank last week.

Madsen has denied any wrongdoing.