Todd McNeal, chief of Northern California's Twain Harte Fire Department said in a recent community meeting he didn't know the exact cause of the Rim Fire but it was "highly suspect that there might have been some sort of illicit grove, a marijuana-grow-type thing."
McNeal has 23 years of experience at the U.S. Forest Service, the National Park Service and other agencies in the Sierra Nevada.
McNeal's comments on the fire's possible cause can be seen at the 6-minute mark of this YouTube video.