The ex-officer, Christopher Dorner, has eluded authorities in a manhunt that has lasted days.
Late Sunday police evacuated a home improvement store in Irvine after a caller said he saw someone resembling Dorner.
Los Angeles police spokesman Gus Villanueva said the caller reported a sighting of Dorner on Sunday. Police were sent to the area, but Mr. Villanueva couldn’t say whether the tip has turned out to be legitimate.
The search since Thursday evening had focused on mountains 80 miles east of Los Angeles where Dorner’s burned truck was found. But authorities have found no recent signs of him.
Authorities have been working to protect dozens of families considered targets based on Dorner’s Facebook rant against those he held responsible for ending his career with the Los Angeles Police Department five years ago.
Among those the 33-year-old Dorner is suspected of killing is a Riverside police officer.
On the fourth day of the manhunt, authorities put up a $1 million reward for information leading to his capture.
“We will not tolerate this reign of terror,” Los Angeles Mayor Antonio Villaraigosa said
Authorities have been in Irvine to protect a police captain mentioned in Dorner’s posting. Police also looked into a taunting phone call to the father of the woman they believe Dorner killed last week.
Two officers who requested anonymity said authorities are trying to determine whether Dorner made the call telling retired police Capt. Randal Quan that he should have done a better job protecting his daughter. The bodies of Monica Quan and her fiance were found shot dead last week in Irvine, marking the start of the high-profile case.
The former LAPD officer served in the Navy, earning a rifle marksman ribbon and a pistol expert medal. He was assigned to a naval undersea warfare unit and various aviation training units, military records show.
In his post, he vowed to use “every bit of small arms training, demolition, ordnance and survival training I’ve been given” to bring “warfare” to the LAPD and its families.