A man who died after allegedly being attacked in an Auckland motel room suffered several skull fractures from blows of "considerable force".
Leonard Nattrass-Berquist and Beauen Wallace-Loretz, both 18, are charged with the murder and robbery of Ihaia Gillman-Harris, 54, at the Ascot Motel in Epsom on December 27, 2014.
Forensic pathologist Dr Paul Morrow, who performed Mr Gillman-Harris' post-mortem gave evidence at the trial in the High Court in today.
He detailed extensive bruising to the dead man's body, on his stomach, back, hand and leg.
Most of the bruises could have been caused by a blunt force instrument, such as a bat or bar, he said.
A scan of his skull showed at least five fractures, which could have come from blows or a significant fall.
"These would have been from blows of considerable force," Dr Morrow said.
Mr Gillman-Harris died during surgery at Auckland Hospital, the same day he was beaten.
Dr Morrow said as surgeons tried to cut into the injured man's skull to relieve pressure from internal bleeding, he went into shock and a narrow heart artery contracted, causing cardiac arrest.
However, it was likely that even if that complication had not happened, he would have died in intensive care after the surgery from the head injuries.
It merely "short-circuited the process".
The cause of death was blunt impact injuries to the head, he said.
There was no alcohol or illegal drugs in his system.
Under cross examination he said he could not rule out that some injuries could have occurred when Mr Gillman-Harris was alone in the motel, after both accused had left.
The prosecution says the teens called Mr Gillman-Harris to pick them up from Pakuranga then convinced him to get cash out, before driving to the motel where they severely beat him, stole his money and took his Range Rover.
The Crown says the teens planned the fatal attack, including putting him in hospital, over text from the back seat of Mr Gillman-Harris' car while he drove them around.
But the defence says Mr Gillman-Harris was a sexual predator who lured the boys, then 17, to a motel room, plied them with alcohol and tried to sexually assault Nattrass-Berquist while Wallace-Loretz was in the bathroom.
The beating had only been in self-defence, Nattrass-Berquist's lawyer, Murray Gibson, said.
The trial continues.