Even the lead prosecutor in the case admitted it was 'something of a whodunnit'. On November 29, 2015, police were called to the Higher Broughton home of Sian Roberts.
Inside the flat they found a scene of baffling and shocking violence. The 36-year-old hairdresser had been stabbed to death.
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Handcuffs and a sex toy lay by Sian's body, and a knife was lying across her left palm. It had been framed to look like a sex game gone wrong.
And, just to muddy the waters even further Joel Gordon, the man who reported finding the mum-of-one's body, was himself a convicted killer.
In fact he was completely innocent of Sian's murder, but the real killer had clearly attempted to throw investigators off the scent. Glynn Williams, also known as Glyn Williams and Glen Williams, came to notoriety in the 1990 Strangeways prison riot.
Williams, then in his twenties, was a key figure in the longest prison riot in British history. The month of disruption started as a protest against poor conditions at the Manchester jail, and led to the authorities losing control of the Victorian prison compound.
Even after hundreds of prisoners surrendered following the first couple of days of disorder, a hardcore of rioters continued to stage a rooftop protest. Williams was among the last five inmates to be brought down from the roof, bringing to an end a 25-day siege.
He was later jailed for 10 years for riot. In the years following his release, he was in and out of prison for burglaries committed to feed his heroin addiction.
Sian, 36, was a hairdresser who had grown up in Cheetham Hill. But the death of her parents and a number of bad relationships had led to her using heroin.
Three months before her death, Sian was introduced to Williams, by then a fixture in the local drugs scene. To Sian he was no more than an acquaintance.
But others within their circle suspected Williams had fallen for her - despite her being in a relationship with another man.
During his trial at Manchester Crown Court, mutual friend, Deana Dyce said: "There was nothing sexual between them, maybe in his head. He actually did tell me he was madly in love with her... he was gonna marry her. I don't know if Sian knew."
The night before her death, Williams had been a guest at a party Sian had thrown at her flat on St Helier's Drive. The morning after, with just two of them still there, Sian went out to get food.
She picked up two full English breakfasts from the Robin Hood cafe in Cheetham Hill and took the meals back to the flat, CCTV revealed. It proved to be the vital clue police were looking for.
In the days following the discovery of Sian's body detectives quickly ruled ruled out suicide or accidental death. They launched a murder investigation and questioned both Joel Gordon and her current partners as suspects.
But then they got the lucky break they needed. Officers came across Williams by chance, spotting him leaving the home of Sian's current partner after his arrest.
They noticed a pair of shoes worn by Williams matched the description of blood-trodden foot prints found at the scene of the crime. With the case against him stacking up, Williams was quizzed by detectives.
But he denied any involvement in Sian's killing, saying he hadn't even been in her house at the time of the murder.
During an initial interview, Williams told police: "I was at her address on Friday into the early hours, until about quarter to three into Saturday and that was my last contact with any persons of this name from that house. From there I went to a friend's house. I stayed there all night and got my head down.
"Saturday morning, I go about my business. But at the end of the day, to me, Sian's death is... I was surprised by it, shocked by it... but I'm also shocked by the fact that I'm labelled as a suspect. I've never had any issues with Sian."
In a second interview, Williams said: "When you get my boots back, I'm going to tell you they're not my boot prints." When police told Williams the prints on the boots were in fact his, he fabricated a new story; that he was the one that found Sian dead and didn't ring police because he was scared he'd be arrested for murder.
What Williams didn't know is that police had also recovered the two breakfasts from the kitchen table. And the one containing black pudding could be linked by DNA on a fork to Williams.
Both meals had barely been touched, suggesting Sian had been killed soon after returning to the property. Her lack of phone and TV usage after she was with Williams, and the fact his bootprints were in her blood at the scene, all suggested he had been the last person to see her alive.
Despite the overwhelming evidence against him, Williams continued to deny he was Sian's murderer. Jurors at the trial were told Sian may have been killed after confronting Williams for stealing jewellery from her.
But, at the time of the killing, Williams had just been awarded a compensation payout and had been buying drugs for female friends. His motives for the murder remain a mystery.
The arrogant career criminal refused to give evidence at the trial. Instead, through his barrister, he tried to pin the blame on the man he saw as the perfect foil - Joel Gordon, who had been sentenced to life in prison for the 1997 knife murder of teenager Craig Pearse in Crumpsall.
The jury saw through his lies. Justice for Sian was finally served when in February 2017 Williams was convicted of her brutal murder and handed a life sentence behind bars, serving a minimum term of 21 years.
Speaking after the sentencing Supt Bob Tonge Senior said: "This was such a tragedy. Glynn Williams tried everything to get out of admitting his crimes and his story changed more than once throughout our investigation. I'm glad we’ve finally got Sian's family the justice they deserve."
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