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Police are hoping that DNA evidence will catch the 'Beast of Birkenhead' forty years after his barbaric killing of florist Diane Sindall, who was 21 at the time.
As part of the investigation proceedings, detectives DNA tested more than 600 men in an attempt to try and solve the 40-year-old slaying, which resulted in the wrongful arrest and conviction of Peter Sullivan, 30, at the time, who spent 38 years behind bars for the crime. Sullivan was branded the 'Beast of Birkenhead' and was pinned as the perpetrator of Sindall's murder, which was a frenzied, sexually motivated attack that happened in 1986.
It was only in May 2025 that Sullivan's conviction was overturned when he alleged that he had been falsely convicted after pressure from Merseyside Police officers. As reported by the Liverpool Echo, as the 40th anniversary of the killing looms, the police say they are doing "everything they can" to try and solve the brutal slaying.
The investigation was already relaunched in 2023 when DNA taken from the scene found a male match. However, no names or arrests have been made since, as enquiries with the National Crime Agency are ongoing to figure out whose DNA it is.
Crimestoppers have an active reward of £20,000 for information given to them that leads to the arrest and conviction of Ms Sindall's killer.
Detective Superintendent Rachel Wilson, the officer leading the inquiry, said in a statement: “It’s unthinkable that 40 years on from Diane’s murder her killer has still not been brought to justice, but I want her family, friends and the wider public to be reassured that we are doing everything in our power to find that person."
She continued by saying that the murder has its own team who are reviewing original case evidence and re-interviewing witnesses, as well as carrying out DNA enquiries and following up with new public tips.
The detective also expressed the force's determination to give answers to Diane's family after four decades. She urged anyone with information to come forward.
Talking about the DNA, Ms Wilson said: "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. We believe the DNA profile will be key to finding the killer and to date have eliminated 575 people and 32 currently under review."
The detective also spoke of how someone could be withholding information on the identity of Ms. Sindall's killer, either because of "fear or a misplaced sense of loyalty". She again urged people to come forward.
What happened to Diane Sindall?
On 2 August 1986, Diane Sindall was murdered. She had completed a late shift at a pub in Bebington working her part-time job, and was travelling home to Seacombe. She had a blue Fiat van, but ran out of petrol on the way. The 21-year-old then got out of her car and started to walk along the well-lit Borough Road towards Tranmere. She was spotted by witnesses between midnight and 12:20 am.
Later, her body was sadly found around midday the next day by a dog walker in an alleyway. She had been violently beaten and had been sexually assaulted. Police said she had "suffered extensive injuries to her body", and died of "a cerebral haemorrhage following multiple blows".
Despite a huge manhunt, the largest in Merseyside's history, Sullivan was the one who was arrested, due to him allegedly giving police different stories of his whereabouts at the time.
Alleged details suggested he was drinking in a pub ten minutes from where her body was found. Reports also allege that after losing a darts match, Sullivan left the pub with a crowbar and had an encounter with Diane.
The aftermath
Sullivan was denied a lawyer at the time as investigators say they were worried about sensitive case details leaking to the public. During the trial in 1987, one dentist gave evidence that said the bite marks on the victim could be matched to Mr Sullivan's teeth, which sparked his Wolfman nickname.
However, his release was secured after DNA matching an unknown male was found.
When he was released, he gave a statement that said: "I feel sorry for (Diane’s family), I really do feel sorry for them and what they’re going through at the moment, where they’re back at square one and not knowing who the person is that killed their daughter."
He continued, saying although he doesn't know what to say to them, he will support them if they want him to, when they find the person, and he'll go to court with them.
