A 9-month-old dog described as having a friendly temperament was shot in early September, and lost his leg as a result of the injury, prompting police to comb through East Bay neighborhoods looking for leads.
The injured pooch, a German Shepherd mix, was brought into the Contra Costa Animal Services Department's Martinez shelter last Tuesday with a wound to its right hind leg.
"He came in limping, basically trying to cuddle up with somebody," said Dr. Bella Kisamov, a veterinarian with Contra Costa County Animal Services.
After further investigation, veterinarians determined that the pup had been shot, resulting in a shattered femur.
"The bullet had shot fragments into the muscle," said Kisamov, who performed a four-hour surgery to remove the bullet that was lodged in the dog's leg.
However, she was unable to save the leg.
"I had follow the track of the bullet because I needed to retrieve it," Kisamov said.
Despite the amputation, the pup is recovering and will be up for adoption in about one week's time.
"His name is Bullet," Kisamov said. "He is very sweet."
The person who dropped off the injured dog declined to provide his name and didn't explain how Bullet was hurt.
According to Steve Burdo with Contra Costa County Animal Services, Bullet had been "clearly shot in the back." But the person who dropped him off at the shelter said only that they "found this dog running on Monument Boulevard."
Investigators say the bullet is the key to tracking down the suspected shooter.
The bullet's caliber will help officials learn "more about the distance it was shot" and "what kind of gun it could have come from," Burdo said.
Whoever hurt Bullet could face animal cruelty charges, if found.
NBC Bay Area's Brendan Weber contribued to this report.