Detectives were pursuing some 700 clues in their manhunt for an ex-cop suspected of a revenge-driven series of killings, Los Angeles police have said, a day after a $1 million (€740,000) reward was posted for information leading to the fugitive's capture.
Christopher Dorner (33), is accused of targeting law enforcement officers and their families in three killings committed in retaliation for his 2008 firing from the Los Angeles Police Department.
His last confirmed encounter with authorities came early last Thursday, when he is accused of having ambushed two policemen at a red light in Riverside, 60 miles (100 km) east of Los Angeles. One of the officers was killed, the other wounded.
That confrontation came shortly after Dorner, a former Navy officer, is suspected of having exchanged gunfire with police in nearby Corona, wounding one officer there.
Riverside County prosecutors yesterday formally charged Dorner with one count of first-degree murder and three of attempted murder in connection with Thursday's shootings and said they had issued a "no-bail" arrest warrant for him.
Riverside County District Attorney Paul Zellerbach told a news conference that the evidence already amassed against Dorner was strong enough to press charges.
"This individual, by both his words and his conduct, has made it very clear to all of us that every law enforcement officer in Southern California is in danger of being shot or killed," Mr Zellerbach said.
Aside from numerous false sightings, the search for Dorner has centred on the San Bernardino Mountains northeast of Los Angeles, where his truck was found abandoned and burning on a fire road near the ski resort community of Big Bear Lake.
The manhunt there has not been abandoned, Los Angeles police spokesman Lieutenant Andrew Neiman said, but detectives were also busy following up an estimated 700 clues and tips from the public in hopes that one of them would lead them to the fugitive.
Dismissing speculation that Dorner's four-day silence may suggest he had taken his own life, Neiman said: "We are operating on the premise that he is still out and about and we are going to find him."
Although public statements by police have suggested Dorner was believed to be acting alone, the US Marshals Service said in court documents filed last week that the agency "has also been tracking the movements of ... a known associate of Dorner".
The purported associate, identified in the affidavit only by the initials "JY," has a family member who owns residential property where Dorner's truck was found burning, but it was not clear whether the individual remained under federal surveillance or had been questioned by authorities.
Representatives of the Marshals Service could not immediately be reached for comment.
The affidavit, filed as part of a criminal complaint charging Dorner with unlawful flight to avoid prosecution, said US marshals had "probable cause" to believe he had gone to Mexico.
That conclusion it said, was based in part on "recent observations of a suspect matching Dorner's description attempting to flee to Mexico" and an alleged statement by Dorner himself during a failed attempt to steal a boat in San Diego last Thursday.
US marshals asked police in the Mexican border town Tijuana on Thursday to be on the lookout for Dorner, and Tijuana authorities distributed flyers with information about him to their patrol units that day, according to Francisco Javier Viruete Munguia, director-general of police and transit there. But he said the effort had so far failed to produce any leads.
US Customs and Border Protection agents joined the manhunt over the weekend by conducting special vehicle screenings of Mexican-bound vehicles at the California border.
Los Angeles Police Chief Charlie Beck has said that the $1 million reward, raised from private donations, police unions, businesses and local governments, was the largest sum ever offered in Southern California in a criminal investigation.
Mr Beck described the manhunt for Dorner as the most extensive ever mounted in the Los Angeles area.
A manifesto posted on Dorner's Facebook page last week claimed he was wrongly terminated from the Los Angeles Police Department in 2008 and vowed to seek revenge by unleashing "unconventional and asymmetrical warfare" on police officers and their families.
Last Wednesday he was named as a suspect in the slayings of a campus security officer and his fiancee, the daughter of a retired Los Angeles police captain who Dorner blamed in his manifesto for his dismissal.
The couple, Keith Lawrence (27), and Monica Quan (28), were found shot dead three days earlier, on February 3rd, in their car on the top level of a parking structure in the city of Irvine, south of Los Angeles.
Dorner had ended his military service two days earlier, and the Navy has not disclosed the circumstances of his discharge.
Mr Beck announced on Saturday a reopening of the inquiry into Dorner's firing to "reassure the public that their police department is transparent and fair".
The Los Angeles Police Department also has opened an investigation into an incident in which two women were wounded when apparently skittish officers opened fire on a pick-up truck resembling Dorner's. The two women were delivering newspapers when they were shot.
Reuters