A mental health patient, released from hospital just days before brutally killing an Auckland pensioner, has been found guilty of murder.

Gabriel Hikari Yad-Elohim has been on trial for the murder of Michael David Mulholland in the High Court at Auckland during the past week-and-a-half.

Today, the jury returned their verdict.

Yad-Elohim will be remanded to the care of the Mason Clinic, Auckland's regional forensic psychiatry services unit, where he has been since shortly after his arrest in September last year.

He was convicted and will be sentenced next month.

Mulholland's body was found in the stairwell at the Western Springs flats where the 69-year-old lived on September 26.

He was beaten to death by Yad-Elohim, a 30-year-old with a history of schizophrenia.

Crown prosecutor Kirsten Lummis had suggested the killing was a result of a "drug deal gone wrong".

A third person, transgender woman Tai Hona Uru, had intended to con and steal from Yad-Elohim, the court has heard. But Mulholland, who has no gang ties, had no drugs to offer when Yad-Elohim knocked on his apartment door.

CCTV filmed the entire assault as Yad-Elohim pulled Mulholland from his flat and attacked him in stairwell for about five or six minutes.

The visual footage, seen by the Herald, was suppressed from public release by Justice Gerard van Bohemen but shows Mulholland being quickly rendered unconscious.

Yad-Elohim was arrested in central Auckland the next day.

However, Yad-Elohim's defence team, led by Annabel Cresswell, said her client was legally insane at the time of the attack.

Yad-Elohim changed his name from Yuuki Watanabe to his Hebrew name, which translated means "hand or messenger of God".

Expert evidence by psychiatrist Dr James Cavney during the trial suggested Yad-Elohim was hearing voices, of Satan and God, telling him he had a "divine endorsement" to kill,

He also saw himself as a Japanese anime character with supernatural powers.

The Herald earlier revealed Yad-Elohim was a patient at Auckland District Health Board's acute mental health unit, Te Whetu Tawera.

Herald sources said he had been released from its care only days before the killing.

The court heard during the trial Yad-Elohim was discharged from Te Whetu Tawera, by Dr Peter (William) McColl, the service clinical director, just three days before killing Mulholland.

"Te Whetu don't appear to want to take any responsibility for that release," Cresswell said during her closing address.

Under cross-examination, several critical questions were asked of McColl, who admitted a factor in releasing Yad-Elohim was because the unit had run out of beds.

However, McColl stood by his decision and said neither he nor his team had "dropped the ball".

"Te Whetu Tawera is a pretty acute place, everyone there is pretty ill," he said.

"It was a good discharge, it was well thought through," McColl said. "This is what we do."

Defence lawyer Matthew Goodwin asked him: "Where are the safeguards, doctor, where are the safeguards for the community with this patient being released?"

McColl replied: "All the pieces were in place to follow up ... he was well, his symptoms had resolved.

"He no longer needed hospital-level care," McColl.

"You say that but three days after release he killed someone," Goodwin retorted.

After Mulholland's death, an external review was also been conducted on the treatment given to Yad-Elohim while he was a patient at Te Whetu Tawera.

But, in what shocked the lawyers involved in the case, the findings weren't disclosed to a court or counsel for Yad-Elohim's legal proceedings.

The review showed the medical notes kept on Yad-Elohim were "misleading".