A West Yorkshire MP is to look into a possible miscarriage of justice over the hanging for a double police murder in the 1950s.
Alfred Moore was sentenced to death after Det Insp Duncan Fraser was shot dead and Pc Arthur Jagger fatally wounded near Huddersfield in July 1951.
MP Barry Sheerman said he would raise the matter with Justice secretary Ken Clarke.
Steven Lawson, a former detective, said he believes Moore was wrongly hanged.
Mr Sheerman said: "I'm starting with a fresh view and will be happy to explore it, I'm on the case".
The case revolves around events after 10 police officers surrounded Mr Moore's farmhouse in Kirkheaton near Huddersfield.
The police arrived late on a Saturday night on suspicion that Mr Moore may have been involved in a burglary.
The police lay in wait around the farm when, in the early hours of Sunday morning, shots rang out and two officers were found to have been hit.
Det Insp Fraser, 45, died in the attack and Pc Jagger, 42, was seriously injured and taken to Huddersfield Royal Infirmary.
Moore was arrested at his farmhouse later, and a dying Pc Jagger picked him out as the gunman from a nine-man identity parade.
In 1952 Moore was found guilty of murder and hanged at Armley Prison, Leeds.
Mr Lawson, a detective in West Yorkshire between 1966 and 1974, has studied the case in detail for several years and feels that the identification parade was flawed and there was no forensic evidence linking Moore to the shooting.
He said: "Opinion has always been divided over this case in Huddersfield.
"If the state has made a mistake it should admit it."