CHICOPEE – A man stabbed and killed a pit bull terrier after it jumped through a barrier in a window and attacked two dogs near Lincoln Grove Park, Saturday night.

A man was walking two dogs on a leash at 9:20 p.m., when the pit bull broke through a cardboard slot next to an air conditioner in a window and launched at the dogs, said Michael Wilk, police public information officer.

The owner of the two dogs yelled at the pit bull and tried to shield his animals. He pushed and kicked the pit bull, but it continued to attack and bite both dogs, Wilk said.

“As a last resort, fearing his dogs would be killed…He removed a pocket knife and stabbed the attacking dog,” Wilk said.

The dog stopped attacking and fled. Police who, were flagged down after the incident, found the pit bull nearby. It had died from the stab wounds, he said.

The man, who told police he was also concerned he may be injured in the attack, said the pit bull was aggressive toward one of his dogs in the past and had attacked it a few weeks earlier, Wilk said.

The owner of the pit bull was upset about the death of the dog, but confirmed the animal had attacked other dogs in the past, he said.

“At this time the investigation is closed as the person was protecting his dogs and himself,” he said.

The injured dogs were taken to an animal hospital for treatment. Officials from TJ O’Connor animal shelter arrived to assist the owner of the pit bull.