That Friday night had been a busy one at The Wellington in Bebington and part-time barmaid Diane Sindall was glad to be heading home.

She'd taken on shifts at the Wirral pub to help pay for her forthcoming wedding. Engaged to her childhood sweetheart, the shy 21-year-old florist had much to look forward to. With her mind full of plans for her future, perhaps that's why she failed to notice her small van was low on fuel.

About 15 minutes into the short journey home, the Fiat Fiorino came to a halt near a roundabout in Birkenhead. Diane had no alternative but to grab a plastic can from the back of the van and start walking along the busy, well-lit road to find the nearest petrol station.

It was a decision with horrific consequences. At some point, shortly after midnight, the young woman was savagely battered to death: stripped half-naked, indecently assaulted, mutilated and her breasts bitten, her body discarded in an alleyway.

It would be another 12 hours or so before it was discovered, on Saturday August 2, 1986. Diane had been beaten about the face, head and body, and sustained multiple fractures. 

Her bra and T-shirt had been pulled up around her neck and her jeans, shoes, knickers and handbag were missing. Poignantly, she was still wearing her diamond engagement ring.

Merseyside Police launched its biggest ever murder inquiry in the hunt for the killer, who was dubbed the 'Beast of Birkenhead'.

Within weeks, after an appeal on the BBC's Crimewatch UK, suspicion fell on a local man, described to The Mail on Sunday as 'not the full shilling' and a 'village idiot'.

After more than 38 years behind bars and repeated attempts to clear his name, Peter Sullivan  has finally been freed

A petty criminal who spent time in borstal as a teenager and with a string of convictions, unemployed labourer Peter Sullivan, then 29, had no history of sexual violence. He was, though, something of an attention-seeking 'Walter Mitty' character who claimed – falsely – to have been friends with 1980s darts champions Eric Bristow and Jocky Wilson and to have had trials with Wolverhampton Wanderers.

Mr Sullivan was charged with Diane Sindall's murder following a 'confession'. He later retracted it, saying it was made under duress from police, but in November 1987 he was convicted of murder at Liverpool Crown Court and jailed for life.

Mr Sullivan has continued to maintain his innocence. Now, after more than 38 years behind bars and repeated attempts to clear his name, he has been dramatically set free after his case was referred by the Criminal Cases Review Commission (CCRC) to the Court of Appeal following the discovery of compelling 'new' DNA evidence.

Sources said there was incontrovertible proof he was not the killer, and it appeared a formality that he would be exonerated in what may be Britain's most grievous miscarriage of justice to date.

For this MoS investigation into the Sullivan case, I spent months tracking down witnesses and police officers who were originally involved in the murder inquiry, and studying dozens of documents, newspaper articles and books relating to Mr Sullivan's prosecution.

I looked into the conduct of Merseyside Police's notoriously macho CID in the late 1980s and early 1990s, when giving suspects a 'good banging' to force a confession was allegedly routine for some officers.

Not only were there troubling questions about why it took so long to uncover the 'new' DNA, but there were major doubts about the credibility of 'bite mark' evidence (related to injuries to Diane Sindall's breasts) presented at Mr Sullivan's trial, as well as disturbing claims that he was initially denied legal representation and the support of an 'appropriate adult' to safeguard his interests (as a vulnerable person of low intellect) after his arrest.

The decision to allow a drug addict/serial criminal, who alleged that Mr Sullivan confessed to murder while on remand in prison, to testify in court was also deeply concerning.

Part-time barmaid Diane Sindall, 21, was savagely battered to death: stripped half-naked, indecently assaulted, mutilated and her breasts bitten, and her body discarded in an alleyway

The Wirral pub where Diane worked to help pay for her forthcoming wedding

The ramifications of this case go far and wide and will engulf the beleaguered CCRC, the Court of Appeal, the now-defunct Forensic Science Service and the Parole Board. Mr Sullivan had been denied parole on ten occasions, largely due to his refusal to admit murder.

Sources told me there were 'shocking similarities' between the missed opportunities in the Sullivan case and that of Andrew Malkinson, who spent 17 years in jail for a rape he did not commit before his conviction was quashed in July 2023 after re-examination of existing DNA evidence proved his innocence. Documents in the case show that the DNA of another man was found three years after he was wrongly jailed.

My inquiries suggested that Mr Sullivan could have been released from prison 17 years ago had the CCRC insisted on new DNA tests being carried out then.

Even more alarmingly, could the real 'Beast of Birkenhead' still be at large? I can reveal that nearly four decades after Diane was laid to rest, and even before Mr Sullivan was officially cleared by the Court of Appeal, a new hunt for her barbaric killer had already started.

The killing: What Witnesses Saw

Friday, August 1, 1986, started like any other for Diane Sindall. She began work at 9am on the florist counter at her uncle's greengrocer shop in Seacombe, a town on the Wirral peninsula, across the Mersey from Liverpool.

At about 5pm, she returned to the nearby flat she shared with her fiance David Beattie, before heading off to The Wellington, about five miles away. Her shift behind the bar ended at 11.30pm and she told colleagues she would probably stop at a fish and chip shop on her way home.

'Goodnight love, go easy,' the then pub landlord Mel John recalls saying to Diane. His wife Ann, 75, adds: 'I walked her to the back of the pub to make sure that she got to her van and told her, "Go straight home, it's late". 

'The next day I was taking my little girl to get some new shoes and saw the police cordon around where they had found a body. When I got back to the pub, I heard that Diane was missing. It was just horrific, just an awful shock.

'Diane was a lovely girl, very inoffensive and very polite – not really a typical barmaid. You get a bit of banter from the men in the pub and if some of the lads were a bit forward with her, she'd go bright red.'

At about 11.45pm, witnesses saw Diane stop her Fiat van near a roundabout in Borough Road, Birkenhead. She was dressed in a white top with black spots, jeans, green high-heeled shoes and was carrying a handbag.

Bus driver Gary Lamb told police he spotted her at 12.03am just before a bus stop.

Another sighting at 12.10am was by a taxi driver looking for fares who saw a woman struggling with a man. He said they were arguing and appeared to know each other.

Steve Wright visits Diane's memorial. She was discovered on Saturday August 2, 1986, 12 hours after she was savagely attacked and murdered 

At 12.15pm on Saturday August 2, a woman dog walker discovered Diane's body in a narrow alley off Borough Road. Diane's van was parked and locked where she left it – just 500 yards away.

Dr Geoffrey Garrett, senior Home Office pathologist for the North West, attended the crime scene. In his 2001 memoir, Cause Of Death, he wrote: 'Her body was to tell a story of terrible frenzy. This was no mere murder. Everyone who saw what he had done to her was shaken. Police, doctor, nurses – and me. There are limits and this was far beyond them.'

He went on: 'The severity of the injuries left little doubt that Diane would have died very quickly once the blows rained down, but she was then dragged backwards and stripped almost naked.' Diane's jeans, knickers, green high-heeled shoes and handbag were not found at the murder scene, he said.

'Two weeks later the items were found burned on Bidston Hill, a little way out of the town,' Dr Garrett wrote. 'They revealed nothing useful in themselves but a witness recalled seeing a man whom he vaguely knew behaving oddly on the hill. The man, he told detectives, was called Peter, had a long nose and tattooed arms – and liked darts.'

On September 22, a plain-clothes policeman walked into a pub in Birkenhead and after talking to local man Mr Sullivan, noticed his pointed nose and forearm tattoos. Three days later, after Mr Sullivan's home had been raided, Dr Garrett was shown a crowbar found there and said it 'could have been' the murder weapon.

After initially confessing, Mr Sullivan then denied being the killer, saying that apart from going to a nearby shop, he'd spent the night of Diane's death watching television with his pregnant common-law wife and twin stepsons before going to bed just before midnight. He was charged with her murder.

The crucial 'bite mark' evidence

At Mr Sullivan's trial at Liverpool Crown Court, which began in September 1987, the prosecution said that bite marks found on Diane's body 'proved' Mr Sullivan was the murderer, earning him the nickname 'The Wolfman'. 

Two expert forensic dentists would identify them as coming from the mouth of the defendant, prosecutor Andrew Rankin QC claimed.

'That is the critical part of the case – so critical that, in my submission, you can forget the rest of the case,' Rankin added.

Leading odontologist Dr Gordon MacDonald, now dead, told the court he had given evidence in 30 cases involving a total of 50 bite marks.

He pointed to characteristics of Mr Sullivan's teeth, including a 2mm gap between his two upper front teeth and four missing teeth.

'I am left in no doubt at all that the marks on Diane Sindall's breasts have been caused by the teeth of Peter Sullivan,' he said.

The murder 'confessions'

During the trial, jurors heard a taped interview in which Mr Sullivan confessed to Diane's murder, adding: 'I don't know why I hit her.'

He described how he stopped her on Borough Road late at night and asked her the time before lashing out with a brick.

But he later said he had been pressured into confessing to murder. 'Why would I go out and kill a girl like that – only 21 years of age? She's got a lot to live for,' he told police. 'I have got no reason to go out and kill anybody.'

Today, there is a memorial tablet on a grass verge near the scene of Diane's murder in that dark alleyway. Flowers and a cuddly toy lie next to it

Prosecutors said Mr Sullivan had come up with 'astonishingly accurate' details of the murder, which only the killer could have known. However, defence lawyers argued that most of the information was already in the public domain – a claim verified by the MoS's recent inquiries.

During the trial, a drug addict/serial criminal came forward to claim Mr Sullivan had, while on remand awaiting trial, boasted about murdering Diane.

Stephen France approached police after hearing radio reports of the case. Then 23, he said Mr Sullivan had told how he smashed her repeatedly over the head with a crowbar. Such 'cell confessions' are notoriously unreliable – and are now inadmissible in UK courts – but at the time France was allowed to give evidence at the trial.

France died from a drugs overdose in 1991.

Multiple appeals are launched

Mr Sullivan was convicted in November 1987, with the judge describing the murder as 'an abomination because of the brutality, ferocity and obscenity of the attack'.

He was told he would have to serve a minimum of 15 years before he would be considered for release. But release was contingent on him admitting to the murder – which he has always refused to do – meaning he served an additional 23 years behind bars.

Mr Sullivan first appealed against his conviction in 2008. His application was rejected by the CCRC, which did not order new DNA tests.

A decade later, Mr Sullivan tried again to clear his name.

His appeal this time was backed by a report by a leading forensic dentist casting serious doubt on the 'reliability' of the bite mark evidence and a consultant psychologist highlighted Mr Sullivan's 'limited intellectual capacity and suggestibility', giving rise to concerns about his 'answers and confessions in police interviews'.

A judge dismissed the application, saying the prosecution did not 'depend' on the evidence relating to bite marks, as the convicted killer had confessed to police and a fellow prisoner.

In a court document seen by the MoS, the judge said it was 'a multi-faceted circumstantial case' and that the other evidence included his presence near the scene of the murder at 'the relevant time', forensic evidence relating to fibres from his clothing, the fact that the fatal injuries were consistent with a tool known to have been in his possession, and his knowledge of details and facts that were not in the public domain 'which were consistent with guilt'.

In 2021, three senior judges rubber-stamped that decision.

Their conclusion that bite mark evidence was not pivotal is curious given the prosecutor's insistence at Mr Sullivan's trial that it was 'so critical that, in my submission, you can forget the rest of the case'. 

Mr Sullivan submitted a new application to the CCRC in March 2021 and new forensic tests were commissioned. The CCRC told the MoS that work on the DNA began in September 2021 and scientists were instructed in February 2022.

The case is referred to the Court of Appeal

Last November, the CCRC released a carefully worded press statement saying it had referred Peter Sullivan's case to the Court of Appeal after a DNA profile was obtained in the new tests that did not match his.

Sources with knowledge of the development told the MoS that the new DNA came from swabs taken 'from intimate parts of Diane's body'.

The CCRC statement added there was evidence to suggest there were possible breaches of the Police and Criminal Evidence Act 1984 (PACE), which regulates police activities, in relation to the interviews, as Mr Sullivan was 'not provided with an appropriate adult and was denied initial legal representation'.

Andrew Malkinson, who spent 17 years in jail for a rape he did not commit before his conviction was quashed in July 2023 after re-examination of existing DNA evidence proved his innocence

The CCRC said when Mr Sullivan applied to them in 2008 he still had a 'direct avenue of appeal open to him' and that 'experts from the Forensic Science Service [FSS] advised that any further testing would be very unlikely to produce a DNA profile'.

This is an extraordinary claim, given that in 2004 Scotland Yard nailed the killer of Rachel Nickell, who was stabbed to death on Wimbledon Common in 1992, through new DNA techniques.

In 2007, forensic advances helped the same force obtain a damning DNA hit in the Stephen Lawrence case, helping to bring one of his killers, Gary Dobson, to justice.

A source close to the case said: 'There are also serious questions about bite mark evidence from the dental expert, and the conduct of the police. Sullivan was vulnerable – he should have had an appropriate adult.

'The CCRC has messed this up badly. They could and should have referred Peter Sullivan to the Appeal Court much earlier, just like in the Malkinson case.

'There are shocking similarities between the cases in terms of missed opportunities. There have been systemic failures at the CCRC.'

New hunt for Diane's killer

Merseyside Police have already re-opened the investigation into the real 'Beast of Birkenhead', they confirmed in a statement.

Detectives have written to hundreds of people who could be a possible match for the new DNA evidence, asking them for a sample. Some of the original witnesses in the case have been re-interviewed.

What about the other sex attacks?

In the wake of Diane's murder, another seven women came forward to say that they had been subjected to sexual assaults in the same area. There are questions to be answered about how thoroughly these reports were investigated.

Who was the mysterious MR X?

During Mr Sullivan's trial, the judge was forced to dramatically halt his summing up after a 'Mr X' – he has never been named – came forward to claim responsibility for stealing Diane's handbag, cash, clothing and her earrings after stumbling across her dead body at 6am.

The man also admitted he was the person spotted running away from Bidston Hill after setting fire to Diane's belongings there the day after the killing.

Mr X was arrested and interviewed several times by police, who concluded that he could not have been the killer because analysis of his teeth impressions did not match those found on Diane's breasts.

The mystery man later withdrew his evidence and said that he had made up the claim after reading newspaper reports and hearing details from a police and hospital source.

In the BBC Crimewatch reconstruction and appeal that was broadcast weeks after the murder, the officer leading the murder hunt said the fire on Bidston Hill was significant.

He added: 'We do feel that the person who was burning Diane's clothing was disturbed.'

A man's sheepskin coat was also recovered from the scene, on which forensic scientists discovered traces of paraffin, probably used to start the fire.

…and who was the driver of the Sierra?

In the Crimewatch reconstruction of the case, detectives appealed for the driver of a white Ford Sierra to come forward.

The car was parked in a bus stop layby on Borough Road, across from the alleyway where the body was found around the time of the murder.

Former pub landlady Ann John, who had waved goodbye to Diane Sindall that fateful night, told the MoS there were always doubts locally about Peter Sullivan's guilt.

'I never thought he fitted the bill. I don't mean to be rude, but he was not the full shilling,' she said.

'He was a bit like the village idiot. I just think he stumbled on the body. People who knew him used to say he might have been a bit of a fool, but he was no murderer.

'Even one detective who came to the pub said to me once that he thought they had not got the right man.'

Mr Sullivan's brother David told the MoS: '[Peter] has done a sentence for something he hasn't done. I have known from day one that he is innocent, and they [the police] knew it, too.'

There is a memorial tablet on a grass verge near the scene of Diane's murder in that dark alleyway. Flowers and a cuddly toy lie next to it.

The inscription reads: 'Diane Sindall. Murdered 2.8.1986. Because she was a woman. In memory of all our sisters who have been raped and murdered. We will never let it be forgotten.'

Nearly 40 years after her death, and on the eve of what would have been her 60th birthday, Diane Sindall is still waiting for justice. And until today, so was Peter Sullivan, 68.

Additional reporting: Simon Trump and Andy Russell