A pensioner suffered such severe and traumatic brain injuries during a brutal attack outside the front door of his home his wounds were akin to a car-crash victim, a court has heard.
Then, just hours after he died, his killer was "maniacally laughing" during an interview with a police detective.
Michael David Mulholland's bloodied body was found in the stairwell at the Western Springs flats where the 69-year-old lived on September 26 last year.
Gabriel Hikari Yad-Elohim, a 30-year-old Japanese man, is on trial for his murder, which began this week before a jury and Justice Gerard van Bohemen in the High Court at Auckland.
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 and the court heard yesterday he was prescribed medication.
His counsel, led by Annabel Cresswell, are seeking a verdict of not guilty by reason of insanity for the man who changed his name to a Hebrew name translated literally to "hand or messenger of God".
Today, Dr Rexson Tse, the pathologist at Auckland City Hospital who carried out the autopsy, told the court Mulholland's head was "subjected to an extreme amount of force".
The injuries he found, a result of blunt force, were so traumatic he said they were normally found on car crash victims.
Yesterday, the jury was shown the CCTV footage of the attack, which shows Yad-Elohim pulling Mulholland out of his apartment and viciously beating him to death in the stairwell.
The footage, seen by the Herald, has been suppressed by Justice van Bohemen but lasts several minutes.
Mulholland was "quickly rendered unconscious", Crown prosecutor Kirsten Lummis said.
However, Tse said Mulholland was alive for at least 35 minutes after the attack but any movements seen during the video he described as "terminal movements, [he was] about to die".
Yad-Elohim was arrested in central Auckland the day after the attack.
Detective Ruth Niu told the court today she first identified Yad-Elohim as police searched for the killer.
She was off-duty at the time and saw Yad-Elohim wearing a white builder's mask.
"There's absolutely no doubt it was him, I have to take action now," she remembered thinking.
But after earlier in the morning seeing the footage of the attack she had concerns about her safety and the public's.
She followed Yad-Elohim.
"I had no radio, no Taser, I had nothing to protect myself," she said.
She phoned Detective Ray Fa'aofo and as he arrived, Niu tapped Yad-Elohim on the shoulder.
"Excuse me, can I have a word?
"He looked at me and said 'no'."
Fa'aofo then made the arrest, with Niu helping to restrain Yad-Elohim as he struggled a little bit.
"It wasn't my fault, it's all covered, it wasn't like that you'll see," Niu recalled Yad-Elohim telling the detectives.
"He just seemed quite defensive," she said.
Later in the police car as the detectives transported the murder accused to the station, Yad-Elohim said, "I'm trained in self-defence".
Niu, who was driving, recalled thinking it was an odd thing to say.
Yad-Elohim also told Fa'aofo his original name was Yuuki Watanabe and was born in Tokyo.
Later at the Auckland Central Police Station, as Yad-Elohim was interviewed by Fa'aofo, the Japanese man said: "I had no intention to kill."
"I will tell you everything," he said.
Yad-Elohim was interviewed with a translator but without a lawyer present.
When Fa'aofo said Yad-Elohim had the right to speak to a lawyer, the accused replied: "What do you think about this case? Do you think I should speak to a lawyer? Yes, I need [a] lawyer."
However, despite Yad-Elohim's request, the detective continued with the interview.
"I think Ray [Fa'aofo] knows 'cause everything cause it was on CCTV," Yad-Elohim said.
"Somebody stole my money.
"I didn't know he was going to die."
After Fa'aofo briefly leaves the room, Yad-Elohim, dressed in a white boiler suit, begins ranting aggressively in Japanese and pacing about the room, a video of the interview shows.
A translated transcript, read by the Herald, says Yad-Elohim mentioned nirvana and Jesus several times while he repeatedly talked to himself.
Yad-Elohim then appears to start "maniacally laughing", Cresswell said.
When Fa'aofo re-entered the room, Yad-Elohim asked for a cigarette.
The accused also said he had now spoken to his lawyer and wished to stop the interview.
Several of Yad-Elohim's answers to the detective throughout the interview appeared nonsensical.
When Yad-Elohim was searched on the police's database a mental health alert appeared underneath his name, Fa'aofo told the court.
However, police, under the orders of Detective Phil Cox, did not take any further action or seek a mental health assessment for Yad-Elohim.
Yesterday, Lummis described the killing as a "drug deal gone wrong".
She said it was Yad-Elohim's desire to obtain drugs which led to "the fatal events of that evening".
Yad-Elohim, who has been remanded to the care of the Mason Clinic since he was charged, suffers from "treatment-resistant" schizophrenia, the court has heard.
He has suffered from mental health issues during the past 10 years.
However, Lummis said, Yad-Elohim's drug use led to the killing and he was well enough to be released from medical care.
The trial continues.