Fugitive ex-cop Christopher Dorner has been charged with the murder of a police officer under special circumstances that could bring the death penalty.
Dorner, who is suspected of killing three people and wounding two others last week, also faces an attempted murder charge over the shooting of another Riverside police officer.
The former LAPD cop, who remains on the run for a sixth day, declared "war" on his former colleagues in a threatening online manifesto.
Police say they are following up hundreds of new leads prompted by a \$1m (£632,000) reward.
A spokesman for the Los Angeles police says they are investigating more than 1,000 new clues resulting from tips from members of the public.
They are also examining CCTV footage obtained by TMZ of Dorner in a sporting goods shop carrying oxygen tanks, two days before the alleged killing spree began.
The reward - made up of donations from local authorities, council officials, police organisations and anonymous donors - was offered at the weekend with the trail having seemingly gone cold.
Police have been searching for Dorner since last week and are protecting the families of 50 officers who are considered targets.
The 33-year-old made clear in a Facebook rant that he holds many of his former colleagues responsible for his being sacked by the LAPD in 2009.
The search has sparked numerous false alarms. Police raced to a home improvement store at the weekend only to discover the reported sighting of Dorner was in fact a couple having an argument in the car park.
Officers also continue to scour the Big Bear area of the San Bernardino Mountains where Dorner's burned-out pick-up truck was found torched. There has been no confirmed sighting of him there.
The search - believed to the largest manhunt in Los Angeles history - has stretched the resources of city's police force. The department is on "tactical alert", meaning officers are staying on duty beyond their shifts.
Meanwhile, a lawyer representing a man whose pick-up was mistakenly peppered with bullets by police hunting Dorner says the officers were reckless.
Surfer Dan Perdue was driving to the beach in Torrance on Thursday when he was stopped by officers guarding the home of a law enforcement official targeted by Dorner.
After driving away, his vehicle was hit by a squad car and, when it spun round, officers began shooting. Mr Perdue was not injured.
It happened just blocks away from another mistaken identity shooting. A mother and daughter delivering newspapers in a pick-up truck were wounded when police opened fire on them.
It has all added to the impression of a region on edge with no sign of Dorner and police convinced he has every intention of carrying out his threat to kill.
The LA police chief has said he will re-open the investigation into Dorner's dismissal from the force. He was fired after being found guilty of making false allegations against a colleague.