According to Alain Benoît, an officer with the L’Assomption/St-Sulpice police force, the girl was walking down Dominique Street in l’Assomption with her 16-year-old female cousin when a dog attacked her.
“For a still unknown reason, the dog … jumped on her and bit her several times,” he said.
The girl, who was visiting her cousin in the small town northeast of Montreal, suffered bites all over her body, with ones on her neck and behind her ear being the worst.
Witnesses said the dog's owner and a neighbour ran out of their respective houses when they heard the girl screaming.
The owner was bitten on the back of her leg in the process of trying to separate the girl and dog, which was a breed of mastiff. The neighbour was uninjured.
Police said they shot the dog because it approached officers while growling and behaving aggressively.
The dog was not fatally wounded, and ran away to hide under a nearby deck. Since then, it has been euthanized.
José Afonso lives across the street from the dog's owner and said he's seen the dog roaming off-leash before.
The girl was initially treated at a local hospital before being transported to Ste-Justine in Montreal.