Results from an autopsy show that the Hamilton, Ont. man who collapsed during a late-night walk did not die as a result of a dog attack.

In a statement on Thursday, police said two men were walking a large dog along Burton Street in Hamilton late Wednesday night when the dog began to attack one of the men, who later collapsed.

Officers said the man was pronounced dead at the scene. He has not been publicly identified, but is believed to be in his 30s.

Hours after the incident, officers said the forensic pathologist examined the body and determined the dog attack was not the cause of the man's death. They have yet to reveal the cause.

A woman who witnessed the attack told CTV Toronto that her husband and another man intervened during the attack, trying to fend off the dog with baseball bats.

"Unfortunately the bat would only stun the dog for a few seconds and then the dog would go right back after the person," the woman told CTV Toronto's John Musselman.

The woman's neighbour told CTV Toronto that the other man, who was not attacked, was carrying the dog's leash, but the dog's collar was not attached to the leash when they intervened.

The neighbour said the dog attacked the man's torso, shoulder and neck, and said that the dog seemed only interested in attacking the one person.

Police and Animal Control officials were able to put an end to the attack by using pepper spray.

The dog is now in the care of Animal Control, being kept apart from other dogs. It's being held in a secure area with cameras. City of Hamilton officials say the dog is a Shar Pei-Fila Brasileiro mix, weighing approximately 45 to 50 lbs.

Anyone with more information is asked to contact Hamilton police at 905-546-3821.

With files from CTV Toronto's John Musselman and CTV News' Peter Akman