Investigators said Kelly Caldwell, 45, was confronted by the dogs at about 9:30 p.m. Tuesday, KABC-TV, Los Angeles, reported.

"I heard that she was going to get a ride from somebody to the store," said Carol Tanner, Caldwell's mother. "Two of the dogs were out and three others joined, I guess, because there are strays running in Yermo."

Authorities were called by a local resident who heard the attack.

"The fire department, as well as sheriff's deputies, arrived on scene and attempted to save her life, but unfortunately were unable to and she was pronounced deceased at the local hospital," San Bernardino County Sheriff's Department spokeswoman Arden Wiltshire said.

Two dogs who were acting aggressively toward investigators have been killed. Authorities said it isn't known how the dogs escaped from their enclosure and whether charges will be filed against their owner, KABC-TV said.