Roseanna (1993) - S0.E5

The unidentified dead body of a young woman is found in Göta kanal, Sweden's longest canal. At first there seem to be no clues to what happened, but thorough research by criminal inspector Martin Beck and his colleagues reveal that she is a librarian from Nebraska, USA. Helped by amateur footage from a cruising ship, they find a likely suspect but still need more evidence before they can arrest him.