Police to probe firing of fugitive US cop LOS Angeles police on Saturday said they would reopen a probe that led to the dismissal of a fugitive ex-policeman being sought in the killings of three people for what he believed was his unfair firing. Police are hunting the snow-blanketed California mountains for Christopher Dorner, a 33-year-old disgruntled former LA Police Department (LAPD) officer who had threatened to murder police in a chilling online manifesto. "I have directed our professional Standards and my Special Assistant for Constitutional Policy to completely review the Dorner complaint of 2007, to include a re-examination of all evidence and a re-interview of witnesses," police chief Charlie Beck said in a statement. More than 100 police searched earlier for Dorner after his car was found in a nearby area, reportedly with weapons and a broken axle. The search has focused on cabins above the ski resort of Big Bear, two hours east of Los Angeles, where Dorner's burnt-out pickup truck was found in nearby woods. Police believe Dorner abandoned the truck when its axle broke, CBS News and CNN reported Saturday, citing anonymous sources. An arsenal of weapons and survival gear was found inside the truck, which Dorner set ablaze Thursday morning, the networks reported. Police apparently also want to make sure that Dorner does not slip into Mexico: at San Ysidro, the world's busiest land border, federal agents wearing body armour and cradling rifles kept a close eye on southbound vehicles, and only two of the four traffic lanes were open at the border crossing. Law enforcement officers in San Diego County remained on heightened alert, but reported no possible sightings of Dorner, who was fired by the Los Angeles Police Department five years ago. "We're at regular staffing at this point, but we have other special units that are monitoring what's going on and if things come up, they'll be able to respond," said Scott Amos, a spokesman with the San Diego County Sheriff's Department. The hunt for Dorner, who police describe as "armed and extremely dangerous," has extended into the neighbouring states of Arizona and Nevada, CNN reported. California authorities launched the manhunt Thursday for Dorner, a naval reservist suspected of killing a couple on February 3 then ambushing two policemen early Thursday, killing one. In an internet manifesto threatening police and their families, Dorner pledged to "bring unconventional and asymmetrical warfare to those in LAPD uniform whether on or off duty." The LAPD, backed by agencies including the FBI, is protecting over 40 possible targets, some of them identified in Dorner's rambling online manifesto. Anger Management star Charlie Sheen meanwhile released an online video on Saturday urging Dorner to call him after the fugitive named him in his online manifesto. In his rambling statement - in which he threatened "unconventional and asymmetrical warfare" against the LAPD - Dorner at one point describes Sheen as "effin' awesome."