Today the search continued search continues on Bear Mountain, Dorner's last suspected location. His burned-out truck was discovered there Thursday at 8:30 a.m., four hours before the call to Quan.
Law enforcement officials tell ABC News some evidence suggests the truck may have been torched and abandoned after it experienced mechanical difficulties.
Search teams comprised of local, state and federal law enforcement officials are combing the mountain on foot, using search dogs and helicopters equipped with infrared cameras.
Teams are going door to door to search nearly 400 homes in the area.
Rugged terrain and a snow storm have hampered efforts to hunt for Dorner, but officials say they have no reason to believe Dorner has left the Big Bear area, even though he has not been seen there.
Dorner, law enforcement sources say, could pose a threat to aviation security. A bulletin issued by the Transportation Security Administration urges aircraft and airport owners and operators to use "an increased level of awareness concerning any suspicious activity during the coming days."
Dorner, the bulletin says, is believed to have received "flight training during his time in the Navy, but the extent of his potential flying skills is unknown.
The "be on the lookout" alert tells operators to secure unattended aircraft and report persons "masquerading as pilots, security personnel, emergency medical technicians, or other personnel using uniforms and/or vehicles as methods to gain access to aviation facilities or aircraft."
Dorner is believed to have had access to military and police uniforms.
Saturday, Los Angeles Mayor Antonio Villaraigosa made a direct appeal to Dorner, telling ABC News, "Mr. Dorner, if you're watching, turn yourself in. You've caused a great deal of death and destruction. It's time that you turn yourself in."
Police described Dorner as black, 6-feet tall and weighing 270 pounds. He has black hair and brown eyes.