California investigators say they've figured out what started the Apple Fire in Riverside County that's already torched more than 26,000 acres.
Cal Fire investigators say the blaze was apparently started when a vehicle with a faulty exhaust system released burning carbon from its tailpipe, igniting some nearby dry brush.
The fire caused the evacuation orders of almost 2,500 homes and destroying several buildings.
Cal Fire officers are asking that anyone who may have seen a vehicle smoking or with mechanical issues on Oak Glen Road around the time the fire erupted to leave an anonymous tip by calling 800-633-2836.