A woman, 63, was mauled to death by four pitballs Thursday morning.
The attack happened in Littlerock, a rural area 65 miles northeast of Los Angeles, as the woman enjoyed a morning run.
Police immediately issued a warning to people about the potential danger and told them to be on the lookout for the animals, the LA Times reported.
The attack was witnessed by a woman in a car who called 911 and honked her horn in an attempt to get the dogs to stop, AP reported.
"When the first deputy on scene saw one dog still attacking the woman, he tried to chase the dog away," Sheriff's Lt. John Corina told reporters.
"The dog ran off into the desert, then turned around and attacked the deputy. The deputy fired a round at the dog and tried to kill the dog, and the dog took off into the desert."
The woman died of her injuries on the way to hospital.
NBC said the department sent an alert at 1:48 p.m. Thursday, stating: "DANGER: Active search for vicious pit bull dogs."
Throughout the day, helicopters patrolled from the air, while officers combed the area on foot for the dogs.
NBC reported a possible breakthrough about 5 p.m. when deputies searched a house and took at least four dogs from a home in the area. Two men appeared to be in custody.