"This is the largest local reward ever offered, to our knowledge," Los Angeles Police Chief Charlie Beck said at a news conference today. This is an act of domestic terrorism. This is a man who has targeted those that we entrust to protect the public. His actions cannot go unanswered. The money for the reward was pooled by businesses, government, local law enforcement leaders and individual donors, Beck said. The reward comes on the fourth day of a manhunt for Dorner, who has left Southern California on edge after he allegedly went on a killing spree last week to avenge his firing from the police force. Dorner outlined his grievances in a 6,000 word so-called "manifesto" and said he will keep killing until the truth is known about his case. Dorner's threats have prompted the LAPD to provide more than 50 law enforcement families with security and surveillance detail, Beck said. Authorities are chasing leads, however they declined to say where in order to not impede the investigation. Dorner's burned-out truck was found Thursday near Big Bear Lake, a popular skiing destination located 80 miles northeast of Los Angeles. Investigators found two AR-15 assault rifles in the burned-out truck Dorner abandoned, sources told ABC News. Full Coverage: Christopher Jordan Dorner Officers have spent the past couple of days going door-to-door and searching vacant cabins. The manhunt was scaled back to 25 officers and one helicopter in the resort town today, according to the San Bernadino Sheriff's Office. On Saturday, Beck announced he would reopen the investigation into Dorner's firing but said the decision was not made to "appease" the fugitive ex-cop. "I feel we need to also publicly address Dorner's allegations regarding his termination of employment, and to do so I have directed our Professionals Standards Bureau and my Special Assistant for Constitutional Policing to completely review the Dorner complaint of 2007; To include a re-examination of all evidence and a re-interview of witnesses," Beck said. Dorner is suspected of killing Monica Quan and her fiancÃ© Keith Lawrence last Sunday in their car in the parking lot of their Irvine, Calif., condominium complex. Quan's father, Randall Quan, was a retired captain with the LAPD and attorney who represented Dorner before a police review board that led to Dorner's dismissal from the force in 2008. On Wednesday, after Dorner was identified as a suspect in the double murder, police believe he ambushed two Riverside police officers, killing one and wounding the other. The next day, Randall Quan reported he received a taunting call from a man claiming to be Dorner who told him that he "should have done a better job of protecting his daughter," according to court documents documents. Anyone with information leading to the arrest of Christopher Dorner is asked to call the LAPD task force at 213-486-6860. ABC News' Dean Schabner, Jack Date, Pierre Thomas, Jason Ryan and Clayton Sandell contributed to this report.