WHAT happened behind the locked door of Matthew Williams' room to trigger his horrific and fatal attack on Cerys Yemm at the Sirhowy Arms Hotel in Argoed on November 6 2014, will never be known.

But the appalling results of the violence he inflicted upon the 22-year-old from Oakdale are seared into the memories of those who walked in on him during his onslaught.

Hotel owner Mandy Miles, who unlocked 34-year-old Williams' door after residents reported screams from inside, told the inquest she had tried to forget the scene.

And the police officers she summoned recounted how they feared for their lives when confronting Williams.

PC Alan Cotterell had "never been more scared" and told the inquest jury he was convinced that had his Taser not worked when he fired it, "I would not be sat here today."

PC Cotterell's colleague PC Kelda Griffiths was similarly fearful, knowing Williams disliked the police and appeared to have killed someone. She told the inquest that before entering Williams' room "I said 'love you mum and dad'. I didn't know if I would survive this incident."

Williams was tasered four times by PC Cotterell during the ensuing struggle, the last three being through direct body contact.

Despite being handcuffed, his legs strapped, and four officers holding him down, Williams still tried to get up, said PC Cotterell, who described him as looking "possessed."

Concerns have been raised by Williams' family over the amount of force used, and the family's representative Nicholas Bowen QC questioned all the officers involved about this.

PC Cotterell felt he had "no other option." He denied Mr Bowen's suggestion that he had "history" with Williams, had gone "over the top" and may have "thought about revenge" while subduing him, given what he had done to Miss Yemm.

Mr Bowen also raised concerns about how Williams was subsequently restrained and his health monitored, and questioned his transportation from the hotel in an ambulance chair, as his condition deteriorated, his head "lolling forward."

On reaching the foot of the stairs, Williams had stopped breathing, and resuscitation attempts in the ambulance were unsuccessful.

Pathologist Dr Stephen Leadbetter, who carried out a post mortem examination on Williams' body, said the way he was transported may have contributed to his decline in health, but he could not be sure. Williams was subsequently found to have suffered a heart attack.

Mr Bowen QC asked him whether it was “bad practice” for paramedics to allow Williams’ head to “lollop around like a ragdoll.”

Dr Leadbeatter said it may have been a factor in his decline, but did not know its significance as he did not know Williams' condition at the top of the stairs.”

He cited the factors involved in Williams' death as a struggle against restraint, including the use of a Taser, his history of schizophrenia, and the taking of amphetamines and cannabis. But he was unsure which was the most significant.

Toxicologist John Slaughter told the inquest Williams' behaviour when confronted by police was consistent with someone in a state of "excited delirium."

This can manifest, he said, in insensitivity to pain, animal-like noises, unusual strength, and willingness to resist. He concluded that amphetamines were the most likely cause.

The inquest was also told of Williams' long term struggles with mental illness, and of concerns over lack of medication and support to help him with this, in prison and following his release on October 23 2014, two weeks before he killed Miss Yemm.

PC Alison Perry and Williams' probation officer Nick Tetley, members of an integrated offender management (IOM) team in Blackwood, told the inquest that because Williams had completed his sentence and was not subject to licence conditions, they could not force him to engage with them and use the support services available.

Both said Williams made it clear at a meeting in prison before his release, that he wanted nothing to do with them, and just wanted to get on with his life.

Williams' mother Sally Williams told the inquest her son wanted medication on his release from prison, but did not get it.

She said she thought both deaths were avoidable, and was particularly critical of PC Perry, whom she thought could have done more to provide support for her son.

Concerns were also raised over Williams being housed in the Blackwood area, when he had wanted to live in Newport, to start a new life.

Inquiries were made with Newport's housing department on the day of Williams' release, but an application was delayed as his father, Christopher Williams, did not have the evidence with him to prove he had lived in the city for five years.

Mr Williams said they approached Caerphilly council for temporary accommodation while the Newport application was pursued, and a place was found for his son at the Sirhowy Arms Hotel.