Police had produced a photofit of a man seen in the area. Ann recognised the face but could not put a name to it – until after Sullivan’s arrest. When she told officers the person in the image was “one of the Irish lads who used to drink in our pub years ago”, she says they dismissed it. As she tells the podcast: “I’ve opened a box of frogs up, maybe. And they don’t want any more frogs to bounce out.”

“You know what the police are like,” she tells me. “They need someone to be up for it.” Ann, now 77, shared the information again after the force reopened the investigation in June 2023 and sent an officer to her door to collect her husband’s DNA, as part of a new wide-ranging campaign of DNA testing. She says the man she had recognised died in 1986, but suggests that because he had children, their samples could eliminate him from the inquiry.

The series also hears from an anonymous former Birkenhead criminal investigations detective who responded to an earlier sexual assault on Borough Road by requesting all the files relating to similar offences in the area, receiving two full boxes.

“Even at a glance, I was struck by the number and the seriousness of the assaults and rapes,” he says. “I couldn’t understand why there wasn’t already a focused investigation in place.”

“As I went through them, I could see that a number of the offences shared a similar pattern. Many occurred in and around Borough Road and the adjoining streets, and they were often in alleyways. There was a clear indication of escalating violence across a number of those attacks.”

Convinced that the pattern “suggests a single offender”, he reported his concerns to a detective inspector and said he was advised to return the files “and not to pursue the matter further”. But he held on to the material for a bit longer “and the more I looked at it, the more concerned I became. In my view, it was moving towards something far more serious”.

He raised his concerns again, with a detective superintendent, but says the instructions he received had been the same. About a week later, when Sindall was murdered, the detective returned to the office to find “that the files I’d been working on were no longer there”.

Both of those superiors are now dead. Asked why a warning was not released before Sindall’s murder, Merseyside Police told the BBC: “This happened 40 years ago and we’re not privy to the information that would have been provided to reassure women in the community at the time.”

The podcast also illustrates how much the relationship between the police and media has changed since the 1980s. Thompson is described in the series as having been “in and out of Birkenhead police station – feeding information from Merseyside Police to the public to try and get new leads”. In contrast, crime journalists today have complained recently that some forces do not even have a press office phone number on their websites.

“Merseyside Police declined to do an interview”, Graham tells listeners. And under “Notes to Editors” on the Criminal Cases Review Commission (CCRC) press release responding to the quashing of Sullivan’s conviction, point number one reads: “There will be no media interviews.”

“Times have changed,” says Thompson, who recalls the bread and butter of his job being every morning “ringing round the various divisions to speak to the detective superintendents and chief inspectors”.

He did not “get any sense [the police] were the type of men who would be capable of fitting someone up in a case of this seriousness,” but added that “they were under enormous pressure to find the person that had done it”.

Sullivan first applied to the CCRC for help in 2008, but was rejected. Two years after Sullivan asked the Court of Appeal in 2019 to look at the now-discredited expert testimony that linked his teeth to the “horrific bite marks” on Sindall’s torso, the court found that the evidence was not essential to the conviction. This was news to Thompson, who recalls the odontologist’s courtroom slide show with a laser pointer being “presented by the prosecution as probably the most critical piece of evidence”.

At the Court of Appeal hearing that finally freed him, the three judges offered “our condolences to the bereaved” and wished to “repeat our thanks to counsel”, but there was – and remains – no apology to Sullivan. The only words directed at him on that day were to tell him to sit down.