WEST COVINA, Calif. (AP) - A woman was asking a 911 dispatcher for help when her pleas were interrupted by gunshots, then silence. She was shot to death.

The woman told the dispatcher someone was trying to break into her home in upscale West Covina, Los Angeles County sheriff's Lt. Dan Rosenberg said. "Deputies heard gunshots followed by silence and an open phone line," he said.

Deputies arrived at the house, 20 miles east of Los Angeles, a few minutes after Wednesday's late morning call.

The woman, whose name was not released by police, had been shot several times. Paramedics pronounced her dead at the scene.

"At this point we believe it was a burglary gone awry," Rosenberg said.

Investigators are trying to determine if anything was taken, Deputy Luis Castro said.

While police were investigating the shooting, a man arrived at the home asking about his wife.

When he heard that the woman had been shot and killed, he collapsed and started to cry, saying "No! She just called me. You lie."

The man was placed in a patrol car and taken to a sheriff's station, police said.

Witnesses said they saw one or more men running from the house, Rosenberg said.

Investigators used bloodhounds to conduct yard-to-yard searches.

No arrests had been made by Thursday morning, deputies said.

As a precaution during the search, a high school and an elementary school were locked down for about two hours, police Lt. Dan Brooks said.