What was responsible for the unidentified man's death remained a mystery Thursday, with shaken area residents trying to piece together what happened.
Police emphasized, however, that the animal had attacked.
"There was absolutely a dog attack, absolutely. We're confirming that. We're also confirming that that was not the cause of death," Hamilton police spokeswoman Catherine Martin told The Canadian Press.
The man was out walking the dog with another man just after 11 p.m. when the incident took place.
A passerby with a baseball bat tried to fend off the animal, and police responding to a flurry of neighbours' 911 calls found the man on the ground. Officers used pepper spray to deter the dog before it was eventually captured with the help of an animal control unit, police said.
After an autopsy determined the dog attack was not what caused the man's death.
"There's no credible evidence that a dog attack was material in the death process here," said Dr. Jack Stanborough, regional supervising coroner for the Hamilton region.
"My understanding is there was a dog attack, now whether that was before the death or after the death or during the process I can't tell you...but I don't see a significant role for the dog attack causing the death."
The man did appear to be injured in the attack, he added, but those injuries were "not material" in his death.
Figuring out just what killed the man will likely take months, Stanborough said, as further testing has to be conducted.
Contrary to initial reports that described the dog as a pit bull — a breed banned in Ontario — the dog has been identified as a sharpei-fila mix, weighing about 20 kilograms, and is currently being held by Hamilton's Animal Services department.
The animal will be held in quarantine until police and the coroner's office complete their investigation.
"Even if it didn't kill the man but it was still vicious and it still attacked the man, it could still be put down," said city spokeswoman Ann Lamanes.
The attack caused a stir among those living in the area, with many waking up to police cars and a marked crime scene on their street.
Mark Wall, who lives one street away, could hear the attack as he sat on his front porch Wednesday night.
"I heard those screams and I thought some guy was getting punched out," said Wall, who described the area as a rough neighbourhood. "He was screaming for his life."
Not wanting to get involved in what he thought was a bad fight, Wall went inside his house and only found out through a neighbour Thursday morning that what he heard had been the dog attack.
"It's horrible," he said. "That's in my head. And that's haunting me."
James Cox also heard the man's screams, as well as the dog's barks.
"The guy was hollering. At first I thought it was a woman screaming," he said. "The dog was growing and barking."
The commotion lasted about 10 minutes, said Cox, who lives a block away.
Police said the man died at the scene.
"The man was collapsed when police officers arrived and the dog was still attempting to engage," said Const. Steve Welton.
"It's unfortunate that it's happened like this in our community. It's a very tragic event."
— By Diana Mehta in Toronto
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