Diane Sindall, 21, was raped and murdered by a killer dubbed the “Beast of Birkenhead” in Wirral, Merseyside, in the early hours of 2 August 1986.

Image:Diane Sindall was murdered in 1986. Pic: Merseyside Police

The family of a woman who was murdered almost 40 years ago have appealed for people to come forward with information after DNA evidence showed the man believed to be her killer was wrongfully convicted.

Diane Sindall, 21, was raped and murdered by a killer dubbed the “Beast of Birkenhead” in Wirral, Merseyside, in the early hours of 2 August 1986.

For decades, investigators from Merseyside Police thought they had caught her killer: a local man called Peter Sullivan.

Mr Sullivan, 68, had always maintained his innocence, and he was freed last year after new tests showed his DNA – unearthed due to scientific advances – was not present in semen samples collected at the scene.

By the time his conviction was overturned, Mr Sullivan had spent 38 years in prison. It is the longest miscarriage of justice in UK history.

Ms Sindall’s family’s appeal on Crimewatch Live is their first statement since the conviction was quashed.

Image:Peter Sullivan spent 38 years in jail for the killing before he was freed last year. Pic: Reuters

“Diane was 21 years old with so much to live for. She had a beautiful heart and soul, and was full of love, fun and laughter which could brighten your day,” they said.

The family said Ms Sindall’s loss “has been felt throughout our everyday lives with a heartache that will never heal”.

“We cannot put into words what we as a family went through at the time of her death, and we are now reliving that terrible time and all that it brings once again,” they added.

They urged members of the public to contact police “no matter how small or insignificant you think your information is”.

New reward to catch ‘Beast of Birkenhead’

Detective Superintendent Rachel Wilson said Merseyside Police “will leave no stone unturned” to find Ms Sindall’s killer.

“In 1986, DNA was very much in the early stages and as such was not available to the detectives who originally investigated Diane’s death but her murder was fully investigated by the team,” she said.

“Unfortunately, there is no match for the DNA identified on the national DNA database and we know it does not belong to any member of her family or her fiance at the time.

“We are working with the National Crime Agency, and with their support we are trying to identify the person the DNA profile belongs to, and extensive inquiries remain ongoing.”