BIG BEAR LAKE, Calif.—Authorities are offering a $1 million reward for information leading to the arrest of Christopher Dorner, the former Los Angeles police officer suspected in three killings who is the subject of a manhunt in Southern California.

LA Mayor Antonio Villaraigosa announced the reward at a news conference at LAPD headquarters Sunday.

Some 80 miles to the east, SWAT teams continued to scour snow-covered mountains near where the 33-year-old fugitive's charred pickup truck was discovered Thursday.

Authorities say Dorner has vowed revenge against several former LAPD colleagues whom he blames for ending his career.