A 40-year-old murder case remains unsolved as police hunt the killer of a 21-year-old woman

On August 2, 2026, 40 years will have passed since the murder of 21-year-old Diane Sindall in Merseyside. On the 40th anniversary of her death, police are once again appealing for information that could finally lead them to her real killer.

Peter Sullivan spent 38 years in prison for a murder he always said he did not commit. He was convicted of killing 21-year-old Diane Sindall in Merseyside in 1986.

Today, Sullivan is free after modern DNA evidence helped overturn his conviction. Police have also reopened the case and are searching for the person responsible for Diane’s death.

Diane was killed during the early hours of August 2, 1986. She had been working at a pub in Bebington and was making her way home after finishing her shift.

Her blue Fiat van ran out of petrol on Borough Road. Diane continued on foot. Witnesses later reported seeing her walking in the area shortly after midnight.

Residents also remembered hearing an argument and screams during the night. Diane’s body was found in an alley several hours later.

An investigation showed that she had suffered a violent attack. She had been sexually assaulted and suffered multiple injuries to her head and face. The injuries caused a fatal brain haemorrhage.

Video. This Crimewatch UK video revisits the 1986 murder of 21-year-old Diane Sindall and the investigation that followed. Original video Man of God, YouTube.

Police launched a major investigation and questioned thousands of people. At the time, however, DNA technology was still in its infancy. Investigators eventually focused on Peter Sullivan, who was convicted in 1987.

Sullivan continued to deny responsibility for the murder. Decades later, advances in forensic science gave him another chance to challenge the conviction.

He approached the Criminal Cases Review Commission in 2021. Specialists then reexamined evidence from the original investigation.

The testing produced a DNA profile that did not belong to Sullivan. The discovery became a crucial part of the appeal against his conviction.

In May 2025, the Court of Appeal overturned Sullivan’s conviction. He was released after spending 38 years behind bars for a crime he said he had not committed.

Photo. Peter Sullivan, convicted of the murder of Diane Sindall, attends a Court of Appeal hearing at the Royal Courts of Justice in London, Britain, May 13, 2025.

The new DNA evidence did not identify Diane’s killer. Instead, it gave investigators a new line of inquiry and raised the possibility that the real offender could still be identified.

Merseyside Police had already reopened the murder investigation in 2023. Detectives are now reviewing evidence collected almost four decades ago and conducting fresh enquiries.

Modern forensic methods have also allowed investigators to revisit material that could not provide useful DNA information in 1986. Police say the unidentified DNA profile remains an important part of the investigation.

Hundreds of men have been screened during the renewed investigation. By 2026, more than 575 men had been eliminated from enquiries, while detectives continued to examine other potential lines of investigation.

Police are particularly interested in people who lived or worked near Borough Road at the time. Even apparently minor memories could help investigators reconstruct what happened on the night Diane was killed.

The DNA profile has not produced a match on the national database. Detectives therefore continue to appeal for information that could lead them to the person responsible.

Crimestoppers is offering a reward of up to £20,000 for information that leads to an arrest and conviction.

The case has also raised questions about the original investigation. In 2026, the Independent Office for Police Conduct confirmed an investigation into complaints connected with the police investigation that led to Sullivan’s wrongful conviction.

That review is separate from the current search for Diane’s killer. For investigators, the central question remains the same after four decades: who left the DNA profile connected to the crime?

Diane was only 21 when her life was brutally cut short. Now, modern forensic science has given detectives a chance to revisit the evidence and potentially solve a murder that has remained unanswered for nearly 40 years.