The family of a man who died after being locked up for 20 years for a murder he did not commit have called on police to re-open the case because they are convinced the victim was killed by the Yorkshire Ripper.

Anthony Steel, 52, was found guilty of murdering 20-year-old Carole Wilkinson three decades ago - during Bradford-born Peter Sutcliffe's rein of terror - and was jailed for life in 1979.

But Mr Steel's conviction was finally quashed by the Court of Appeal in 2003, four years after he was released from prison on parole.

Following his death at the beginning of this month, Mr Steel's family are now calling for a fresh investigation into the 28-year-old case.

One theory which has been publicised is that Miss Wilkinson, who made history as the first murder victim to have her life support machine turned off by doctors, was a victim of the Ripper.

Sutcliffe, a former lorry driver of Heaton, Bradford, admitted murdering 13 women and attacking seven more in a seven-year spree.

A former Ripper Squad detective, Dick Holland, who was also involved in the Anthony Steel investigation, has said Sutcliffe was probably responsible for more sickening crimes than he admitted.

But the former detective has previously told the Telegraph & Argus that it had not been "in the public interest" to investigate the matter further.

Now Don Emmott, 48, Anthony Steel's brother-in-law said the family wants to see a fresh investigation into Carole Wilkinson's death to put right what has been described as one of Yorkshire's biggest miscarriages of justice.

He said: "We need to get justice for us and for her family."

Carole Wilkinson was murdered in Bradford in October 1977 on the same day that the body of Jean Jordan, who Sutcliffe also admitted killing, was discovered in Manchester.

Carole Wilkinson was bludgeoned to death with a blunt instrument, later said to be a coping stone, as she walked to work and her body was found in a field off Gain Lane in Thornbury.

Because of her injuries she was, at first, included in the Ripper inquiry. But, because of a lack of manpower caused by one of Britain's biggest ever manhunts, senior detectives ruled her death out of the investigation.

Anthony Steel, then 22, confessed to Carole's murder 18 months later and was jailed for life. The conviction was later quashed after it was discovered that he was mentally handicapped and had been interrogated for two days before making his confession.

Mr Emmott, who now lives in Greetland, Halifax, believes that the police should re-open the case to find out whether she should be added to the Ripper's list of victims.

He said he wanted to clear his brother-in-law's name and allow Carole Wilkinson's family to know the true murderer.

Mr Emmott, who is married to Mr Steel's sister, Angela, 44, said: "I want to see the investigation re-opened and for the police officers to come to see me.

"I hope to produce a document with details showing that it was Sutcliffe that killed Carole Wilkinson.

"I do not want to make any money out of any of the publicity for this. All I want is for justice for Anthony and justice for the family of Carole Wilkinson."

A West Yorkshire Police spokesman said the case had been reviewed after the Court of Appeal decision and no fresh information was recovered. He said: "We are not currently pursuing any active lines of inquiry. We would welcome and consider any new information."

e-mail: marc.meneaud @bradford.newsquest.co.uk