"The deputy was driving by and spotted a pit bull mix aggressively trying to attack a male in an electric wheelchair," Valenzuela said.
The victim managed to turn his chair away every time the dog lunged, avoiding contact with the animal, Valenzuela said.
Fearing the dog would hurt the man, the deputy fired his sidearm at the pit bull, which ran away, unscathed, according to Valenzuela.
Animal control officers located the dog -- and its owner -- less than a half-hour later, Valenzuela said.
Riverside County Department of Animal Services spokesman John Welsh said the 7-month-old male dog was impounded at the department's Riverside animal shelter.
"The dog is quite large... (and) was described to us as having an aggressive nature," Welsh said. "It broke loose from a chain and got out of its yard."
Welsh said because the animal did not bite anyone, the owner will not be punished.
The owner will not be able to reclaim the dog until he mends the fence around his yard to ensure the animal is secured in the future, Welsh said.
In Riverside County, it is illegal to secure an animal by tethering alone, Welsh said.
The owner will have 10 days to make repairs. If the person does not comply and relinquishes the pit bull to the Department of Animal Services, the dog likely will be euthanized, according to Welsh.
- Get more local news headlines from the Inland Empire
- Have a news tip? Send your tips, video, or pictures
