BIG BEAR LAKE, Calif. — The search for the former Los Angeles police officer wanted in three killings continued throughout Friday here, even as a blizzard covered the mountains with a foot of snow. But as no new traces of the suspect were found, the authorities wondered if he had somehow slipped through their fingers.

Law enforcement agencies from across Southern California had been on a regionwide manhunt since early Thursday for Christopher J. Dorner, 33, a former Navy reservist sought in connection with the shooting deaths of three people and the attempted shootings of several police officials.

Over the course of the week, since the first killing on Sunday, Mr. Dorner had been spotted all over Southern California, from Riverside to San Diego. His trail seemed to lead here on Thursday when a burned-out pickup truck found at the base of the mountain was identified as belonging to Mr. Dorner. Law enforcement followed tracks from the car into the nearby woods. With only a few routes in and out of town, they were confident they had Mr. Dorner cornered.

More than 100 law enforcement officers have spent the last two days combing the area, going door to door overnight, taking special care to investigate remote cabins and other vacation homes whose owners were away, and scanning the area by helicopter.