When Vincent Tabak told friends at a dinner party soon after Joanna Yeates's death that her killer must have been a "detached, crazy" person, it would have seemed an innocent contribution to a lively debate.
No one at the table thought that he, more than anyone else, knew the truth.
After all, the 33-year-old Dutchman appeared polite, considerate, hard- working and highly educated. He was noted for his quiet but cheerful nature.
Yet the seemingly devoted boyfriend was in fact a fan of submission pornography in which women were choked, bound and gagged. His computers revealed violent images of females being held by the neck, degraded and sexually abused. He surfed sex sites for escorts, using the cover of business trips for his assignations.
He had been looking at online pornography the morning of 17 December 2010 – the day that prosecutors said he turned from "observer to participator", and murdered Miss Yeates.
His double life can only be revealed now, after a jury yesterday rejected his claim that he had strangled his 25-year-old neighbour to death by mistake. After three weeks of harrowing evidence and 14 hours of deliberation, jurors found him guilty of murder by a majority of 10 to 2.
Tabak – at 6ft 4in, a giant of a man compared to his victim, who struggled so hard in vain, sustaining 43 injuries – simply hung his head in the dock when he was sentenced to life with a minimum term of 20 years as police revealed that his DNA had been sent out to forces around the UK, as well as his native Holland, to see if it matched with other sex attacks.
It had been a "dreadful, evil act" against a vulnerable young woman, which caused "devastation to her family", said Mr Justice Field. "That wicked act ended the life of a young woman who was entitled to expect a life of fulfilment. In my opinion you are very dangerous. You are also thoroughly deceitful, dishonest and manipulative. Joanna died a dreadful death at your hands. She died in pain, beset with fear, struggling desperately for her life."
For Joanna Yeates's parents, David and Teresa, as well as her boyfriend Greg Reardon, 28, the verdict brought little relief. Her parents said they wished it was possible for him to receive a death sentence.
"This trial has had little effect on our lives. We still lost our daughter," her parents said in a statement. "We saw no emotions of remorse or regret for what he did to Jo. All we heard were words of self-pity. The best we can hope for him is that he spends the rest of his life incarcerated where his life is a living hell, the recipient of all the evils, depravations, and degradations that his situation can provide."
Bristol Crown Court heard how Ms Yeates, a landscape architect, had enjoyed drinks with colleagues before heading home that night to the flat in Clifton she shared with her boyfriend. Within minutes of her return, her neighbours heard screams as she fought for her life. Tabak strangled her to death. He then bundled her body into the boot of his car and drove to Asda, where he texted his girlfriend Tanja Morson at her works party to say he was "bored".
Tabak, who admitted manslaughter but denied murder, would later insist he had misread Ms Yeates's "flirty" signals and simply placed his hand over her mouth when she screamed because he tried to kiss her. The prosecution called him a "deceitful liar" and the jury agreed.
Even his own defence team acknowledged that when he drove her body to a lane by a quarry three miles away and dumped it, where it would eventually be found on Christmas Day, his behaviour was "frankly disgusting", leading to "untold anguish and agony" for her family.
Upon his return home two days later, Mr Reardon felt an increasing sense of panic when he called her mobile phone only to have it ring in the flat.
Yet as one young man was becoming increasingly desperate for news, on the other side of the wall Tabak was on the internet, researching how a body decomposes, rubbish collection times and different sentences for manslaughter and murder.
On 28 December, he and Morson travelled to the Netherlands where they spent New Year with Tabak's family.
But the couple could not escape the news, and it was here that they learned that Ms Yeates' landlord, Chris Jefferies, had been arrested. Tabak saw an opportunity to frame the former school teacher, and called Avon and Somerset Police to tell them that Mr Jefferies' car had been moved on the night of the murder.
Ironically, it was this attempt to implicate Mr Jefferies that led police to turn their attention to Tabak. Detectives travelled to the Netherlands to interview Tabak about his claims, and after doing so, took a DNA swab which would eventually link him to the murder.
Pretending to continue with his life as normal, Tabak was alternating between scanning websites on the case and watching domination porn. Nigel Lickley QC, for the prosecution, revealed that when police seized his computers they found submission pornography of women being choked, bound and gagged. Amongst a series of images, one picture showed two unclothed women tied up in the boot of a car. Another contained an image of a blonde girl who looked like Miss Yeates, wearing a pink top and jeans similar to the clothes she wore on the night she died.
All of this evidence can only be revealed now – it was kept from the jury after Mr Justice Field ruled that Tabak's sex life proved nothing in the case. However, yesterday when the prosecution attempted to keep it quiet, insisting there was an ongoing investigation, the judge ruled that it was now time for it to be made public.
The new evidence revealed that, just weeks before the murder, Tabak had met escorts during a six-week business trip to Los Angeles, on one occasion booking into a hotel under a false name. He had also perused websites offering sex and made phone calls to escort agencies while on another trip to Newcastle six months earlier. He had surfed the internet for live chat and strippers and called escort agencies, Mr Lickley said.
Born in the village of Veghel near Eindhoven to a father who worked in the airline industry, Tabak was a straight-As student at school and longed to be an architect or engineer. He grew up with his brother Marcel and sisters.
He gained a PhD at Eindhoven University of Technology, moving to Britain in 2007 to join architectural company Buro Happold. In the introduction to his PhD thesis, Tabak wrote of the sorrow caused by the death of his father but the joy of finding a new relationship. Miss Morson persuaded him to move to Bristol, where he would eventually become the neighbour of Joanna Yeates.
* Tabak is facing further questioning by police after being jailed for killing Joanna Yeates.
Nigel Lickley QC told the court it was necessary for Tabak to be questioned about the matters, but spoke cryptically in order not to reveal the full details.
The prosecutor said following questioning of Tabak a decision would be made as to whether proceedings would be commenced.
Avon and Somerset Police have refused to give any more information on what Tabak may be questioned about.
At a press conference held yesterday the senior investigating officer on the case was asked if Tabak might have carried out any other attacks.
But Detective Chief Inspector Phil Jones said there was no indication that he is linked to any other offences.
Police added they had been in contact with officers in Los Angeles and in Holland in a bid to build up a bigger picture of Tabak.