A Danish inventor charged with murdering Swedish journalist Kim Wall in his home-made submarine had video footage on his computer showing women being violently killed, a court heard on Tuesday.

A police prosecutor said officers found images "which we presume to be real" of women being strangled and decapitated on the hard drive on Peter Madsen's computer in a laboratory he ran.

That, together with new post-mortem evidence showing Wall was stabbed in her rib cage and genitals "around or shortly after her death," was adding to the case against Madsen, the prosecutor, Jakob Buch-Jepsen, told the Copenhagen court.