In an open letter posted on Facebook, a woman with the profile name Amy Leigh said the six-year-old pit bull, known as Pandora, belonged to her sister.
CBC News contacted the owner of the Facebook account, whose full name is Amy Fairbridge, who confirmed she had written the posting and that her sister Samantha Fairbridge was the owner of the dog.
According to reports, the pit bull and pug approached each other at the seaside park on Vancouver's Westside on Wednesday afternoon.
The larger pit bull suddenly bit down on the neck of the smaller dog. Unable to separate the animals, the pug's owner pulled out a folding knife he was carrying and stabbed the pit bull, killing it.
Amy told CBC News that although it was initially reported that the incident occurred while the pit bull was with its owner, it was in fact her sister Samantha's roommate who had taken Pandora down to the beach.
Amy wrote in her post that the pit bull was on a leash when it encountered the pug. She also says the pug, which she claims was not on a leash — in violation of the park rules — was not under its owner's control.
'You deserve to die'
In her Facebook post Amy alleges, "He screamed these words 'You hurt my dog. You deserve to die.' And then he took out a knife and repeatedly stabbed Pandora until she died. And as Pandora lay their lifeless, this old man fled the scene with his dog in an SUV."
In comments under the post, Amy's sister and dog owner Samantha alleges that the man continued stabbing the dog after it was subdued, killing it unnecessarily.
"After the first stab wound, after Pandora lay on the ground in pain, this old man continued his brutal attack. He shouted profanity, as he stabbed her over and over again, calling Pandora a bitch, saying that she deserves to die."
The pair defended the pit bull in the Facebook post, saying it had never been aggressive or attacked before and they often let it play with Amy's four-year-old daughter without concern.
Police say they have spoken to both owners and are not considering any charges in the incident. The SPCA says it will perform a necropsy on the pit bull to determine if it suffered when it died.