Police in a rural part of southwestern Quebec are investigating a horrible case of animal cruelty after a black Labrador retriever and her puppies were abandoned on the side of a quiet road -- three of whom had been shot in the head with a nail gun.

The mother and her eight pups had been left for dead when Ken France and Genevieve Sabourin rescued them, after they got a call from a friend who discovered the dogs next to an isolated road in Monteregie.

France and Sabourin said it was a miracle that only two of the puppies died.

"My reaction at that time was of horror," Sabourin recalled. "I was just horrified."

Rescuers came across the mother first. She led them to a ditch 20 feet away where one of her puppies was shivering in the snow.

"Obviously to me she was not going to make it. She was dying," Sabourin said.

She began petting the dog and felt something strange on its head.

"Then I looked and I saw that it was metal, like two pieces of metal that had been punctured in the brain," she recalled.

"This is when I said: ‘something's really, really wrong here.'"

Another puppy lay dead in a garbage bag nearby. It had also been shot by a nail gun.

Animal protection services took all the dogs to the vet. The mother, who also had a long nail lodged in her brain, was treated there and is recovering.

The six surviving puppies have been adopted. But police are investigating who abused the dogs.

Meanwhile, both France and Sabourin say they're struggling to understand a crime, which they say still haunts them.

With a report from CTV Montreal's Aphrodite Salas