The Rim fire, which has burned into Yosemite National Park and threatened a vital water supply to San Francisco, was started by a hunter who let an illegal fire “escape,” the U.S. Forest Service said Thursday. The fire was not started by a marijuana growing operation, despite rumors to the contrary, the U.S. Forest Service’s investigation unit and the Tuolumne County district attorney’s office concluded. The hunter has been identified and his name is being withheld pending further investigation, officials said. The hunter has not been arrested. The Rim fire began Aug. 17 near Jawbone Ridge in the Stanislaus National...