Antonie Dixon was dehydrated, malnourished and believed authorities wanted him dead in the days leading up to his suspected suicide, an inquest into his death has been told.
Coroner Garry Evans is presiding over the inquest into the death of Dixon, whose 2003 attack on two women with a Samurai sword and the murder of a man shocked the nation.
The inquest, held at Auckland District Court, heard evidence from prison psychiatrist Krishna Pillai, who saw Dixon numerous times between 2003 and was with him on the day of his death on February 4, 2009.
"Mr Dixon was a very challenging individual with an extremely changeable and unreliable presentation," he said.
"I formed a working diagnosis of severe personality disorder with mixed narcissistic and anti-social personality traits."
However, Dixon had a long history of exaggerating his symptoms - apparently for personal gain - and was an "adept liar", which made diagnosis difficult.
"From time to time he carried an obsessive religiosity in relation to his faith, believing he was one of the last 144,000 who were mentioned in the Revelation of St John who would be saved. As such he had, it appeared, a profound belief in his own righteousness and his own safe delivery to the afterlife," Dr Pillai said.
On the day of his death, Dixon spoke of fearing for his life.
"He spoke at length of paranoid themes such that he was going to be killed by prison officers and would be dead the next morning," Dr Pillai said.
In his 10 years as a psychiatrist, Dixon was probably the "No 1" patient he had ever treated in terms of his ability to "confuse obfuscate and manipulate".
The inquest was told Dixon strangled himself with a piece of "suicide-proof" blanket.
Dixon was transferred from Auckland Central Remand Prison (ACRP) to Auckland Prison at Paremoremo because he required a "tie-down bed" that was unavailable at ACRP.
Coroner Evans said Dixon had displayed self-harming behaviour and violence which had become "unmanageable" in the days prior to his death
"The evidence will show that he had twice headbutted himself quite seriously at ACRP and that he had attempted, or had been seen making preparations, to carry out the same kind of self-strangulation that he did in fact carry out on February 4."
The prison officer charged with checking on Dixon every 15 minutes at Paremoremo prison's high-risk unit, whose name is suppressed, said he had not been made aware of this.
He told the court that Dixon had appeared "fine" on the night of his death, and had smiled and given a thumbs up sign.
"I came out (of the bathroom) at about 8.50pm and heard a thud and made my way to the cell.
Because of the risk he posed to prison staff, the prison guard needed four guards to be present before Dixon's cell could be opened.
Another three prison officers arrived at about 9pm, by which time Dixon had collapsed on the floor.
The prison officer said he had not been aware that there was an exception to the "four-man-unlock policy" if there was an emergency, but he said he wouldn't have gone in alone anyway.
Toilet paper had been placed over the security camera in his cell, he said.
An Environmental Science and Research report said a post-mortem examination showed Dixon had methamphetamine in his system.
There were also high levels of acetone in his body which, the court was told, was due to Dixon starving himself in the period prior to his death.
The inquest is set to continue tomorrow.