Authorities say they believe a 13-year-old boy set a 2,100-acre wildfire last month in the San Gabriel Mountains north of Los Angeles.

Los Angeles County sheriff's Sgt. David Infante says his department asked prosecutors on Wednesday to charge the boy with arson for the fire that started Aug. 25 in the Angeles National Forest.

The blaze was contained on Sept. 3 and no homes were damaged.

Infante doesn't have the boy's name or other details. He says the teen isn't in custody.

District attorney spokeswoman Sandi Gibbons says charges will likely be filed Thursday.

The fire was dwarfed by another arson in the Angeles National Forest that destroyed 89 homes. The 251-square-mile blaze started a day after the smaller one and is 91 percent contained.