A dog was shot by a police officer on Queen Street North Monday evening after biting a child and lunging at an officer.

Three boys were playing in an alley in the area of Queen Street North and Patterson Street around 4:30 p.m. when a large Brazillian Mastiff called a Fila Brasileiro broke free from its chain and ran at them, police say.

The boys ran, but the dog caught one and attacked him, says police spokesperson Debbie McGreal-Dinning.

"He was located by officers with three significant bites on his body," McGreal-Dinning said. The eight-year-old boy was treated at McMaster Children's Hospital and released, she says.

Just before 5 p.m., police and animal control officers found the dog running loose in an unfenced back yard on Queen Street North. "At that time the dog locked eyes with one of our officers and just went for him," McGreal-Dinning said.

The officer shot the dog to protect himself, she says. The dog suffered a minor wound, and was corralled in the backyard until his owner, a 50-year-old Hamilton man, arrived, she said. Animal control now has the dog in their care.

"Animal control will be investigating the matter further and laying charges," McGreal-Dinning said.

The Brazilian Mastiff can grow to be up to 180 pounds. The breed is legal to own in Canada.