The pathologist in a Dunedin manslaughter trial says the victim was struck six times before he died and may have been strangled.
However, Dr Martin Sage said the evidence from his autopsy did not indicate whether 66-year-old Alan James Fahey died primarily because of the attack or because of his medical conditions.
The victim's flatmate, Jason Karl Blackler, 48, is on trial before the High Court at Dunedin.
The Crown says Fahey allegedly made sexually inappropriate comments about his friend's terminally ill sister during a heavy drinking session on October 25, 2016.
It is alleged Blackler attacked the victim and left him facedown on the floor of the lounge, where paramedics found him dead the next morning.
Sage, a veteran of nearly 10,000 autopsies, said almost all of Fahey's injuries concentrated around the face and throat.
Describing Fahey as having an "exuberant" grey beard, stringy shoulder-length hair, "extensive poor-quality tattoos" and an earring in his left earlobe, Sage said he noted a large laceration on Fahey's top lip, extending to the base of his nose, broken nasal bones and a splitting tear right of his nose, swelling and bruising to his eye sockets and extensive bruising inside his mouth.
Sage counted six blows in all.
"This cannot be a result of falling over, landing on the flat floor," Sage said.
He also found the hyoid bone above Fahey's Adam's apple was fractured.
Aside from the injuries, the pathologist noted lung disease from long-term smoking and severe heart problems.
There was no clear evidence of a heart attack, but sudden cardiac death seldom left any signs, Sage said.
"I can't tell you and that's just how things are," he said.
Sage told the jury yesterday there was no evidence on Fahey's neck of ligature marks or finger marks consistent with strangulation.
The prosecutor pointed to a piece of black material at the scene by the body, asaking if it could work as a ligature.
"Yes, sure," Sage said, adding it might not leave marks but he would not expect it to fracture the hyoid.
The witness also spoke about a "carotid hold" used in judo and by paramilitary, overseas police and bouncers to disable people.
"If you do it properly, the person you are squeezing will black out in five to eight seconds. It's a very effective way of controlling people," Sage said.
If the hold remained in place for a couple of minutes, the victim could die without any internal or external evidence left, he told the court.
But he could not peg that as the likely cause of death.
The question that should be asked, Sage said, was not "Why did he die?" but "Why did he die now?"
The issue for the jury to unravel was whether the blows inflicted on the night caused death or whether the dominant factor was Fahey's existing health complaints.
Earlier, the jury heard from Constable Rhys Davidson who helped arrest Blackler in Moray Pl on October 26.
While awaiting interview at the station, the defendant allegedly told him he wanted to speak to his girlfriend because "he would be doing 10 years".
Despite a bank teller claiming Blackler told her he had beaten someone to death, he told the officer minutes later he could not recall anything after arguing with Fahey the night before.
Davidson said he noticed the defendant's right hand was swollen but when he was invited to step out of the witness box and inspect them again yesterday, he accepted the swelling might have been part of a permanent condition.
The trial continues.