Dec. 1992 A.D. Joshua Tree National Monument, California. This mini-outbreak occured when a vacationing couple (Sharon Parsons and her boyfriend, Patrick MacDonald) went camping in the park. At some point, Sharon was attacked and bitten by a zombie: the likely “culprit” is implied to be Devin Martin (on account of his skin fragments appearing on Sharon’s fingernails), a loner/wildlife photographer who vanished a month earlier. Back at camp, Sharon apparantly zombified in her sleep, and attacked and bit Patrick, forcing him to bash her head in with a rock.
When several witnesses found the gruesome scene, the police made a thourough investigation of the park, which turned up nothing outside the initial scene of the crime (likely implying that Devin either was killed by Sharon, but in a way that didn’t leave any reamains, or wasn’t killed, and stumbled out of the park). MacDonald was last seen (well, alive at least) at a gas station in Diamond Bar, California, reported by the clerk on duty to be half-crazed, nursing a bite wound on his shoulder, and heading west, to Los Angeles.