A distant US relative of Dr Hawley Crippen, executed in London in 1910 for murdering his wife, has failed in a bid to secure a posthumous pardon for him.

The Criminal Cases Review Commission refused to send the case back to the Court of Appeal, saying the applicant was not a "properly interested person".

James Patrick Crippen, 73, of Ohio, a second cousin three times removed, said he was "disappointed" by the decision.

He argues remains found at Crippen's home were not those of his wife, Cora.

He said DNA tests had proved this, casting serious doubt over his ancestor's conviction.

James Crippen has been fighting for years for an appeal, a royal pardon and the release of his relative's remains, which are buried in the grounds of Pentonville Prison, London.