Durham Regional Police Const. Chris Barkwell said the discovery was made while children were at Summer Park in Pickering, Ont., on the weekend.
"Kids were playing around and people wanted us to come as quickly as we could to deal with this dog," he told CBC News in an interview on Monday.
Barkwell said investigators have determined that a woman was walking her dog in a wooded area when her pet found something, ran off with it and dropped in the park.
That object turned out to be the head of another dog.
Another person made the call to police.
"The head was still intact, you could still see the hair and everything like that on the dog, so it was pretty disturbing," Barkwell said.
The remains still had a dog collar attached with the name and address of its owners.
Barkwell said police made contact with the family on Monday.
He told CBC News the family was "devastated" to learn what had happened. The dog, a small terrier, had run away in January and the owners had put up posters and ads on Kijiji in an effort to find it, Barkwell said.
Barkwell said the owners aren't sure if they will tell their children what happened.
The constable said it is not yet clear what caused the dog’s head to be separated from its body.
"It could be just the case of a coyote that got it, which is still a public safety risk … but we’re not sure as of yet," he said.
Anyone with information is asked to contact investigators at 1-888-579-1520 x2858.
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