The death of a 'cannibal' killer who was reportedly found eating a young woman's face in a hotel room is still a complete mystery.
Newly-freed prisoner Matthew Williams collapsed after being tasered by police after killing Cerys Yemm, 22.
Next fashion shop worker Cerys was found in a pool of blood after hotel staff saw Williams, 34, in an act of cannibilism.
An inquest today heard how Williams was arrested at the Sirhowy Arms Hotel in the village of Argoed, near Blackwood, South Wales. He was tasered by officers at the scene.
But the inquest found that the cause of his death cannot be determined until more drug tests are carried out on his body.
Coroner's officer Dave Arnold said: "Officers went to the hotel and arrested and took into a custody a man who became unresponsive at the scene.
"Despite efforts by the police and ambulance personnel, he was presumed dead by paramedics."
Mr Arnold said a post mortem examination carried out found out that the cause of death was "unascertained" pending toxicology and microscopy tests on blood, urine and body tissue.
Gwent coroner David Bowen adjourned the inquest until next April.
An earlier inquest into Cerys' death said she died of "sharp force trauma to her neck and face" in the attack four weeks ago.
Witnesses described how there was smashed china on the floor in the hotel room.
Williams, believed to have been high on a cocktail of drugs after just being released from prison, was tasered by police and died moments later after becoming "unresponsive".
None of her family attended the five-minute hearing at Newport Coroners Court.
Williams' mother Sally Ann Williams has said he was a paranoid schizophrenic who failed to get medical help after leaving prison less than three weeks before his death.
The Independent Police Complaints Commission are also looking at how Williams died just moments after being arrested.
Ministry of Justice chiefs confirmed there will be a serious further offence review because the killer had only just been released from jail.