LOS ANGELES (AFP) - US investigators searched for clues Monday after a small plane taking children to a ski trip crashed in a cemetery in the state of Montana, killing 14 people on board, officials said. The plane, a single engine turboprop, was heading from Oroville, California, just north of San Francisco on a 900-mile journey to Bozeman in the northern state of Montana. However, at some point "they diverted into Butte (Montana) where it crashed ... 500 feet short of the runway" of a local airport, Federal Aviation Administration spokesman Les Dorr said. "We think that it was probably a ski trip for the kids," another FAA spokesman, Mike Fergus, told AFP. Early reports indicated 17 people had been killed when the plane plunged into a cemetery, but the death toll was later revised to 14, officials said. Fergus said the crash occurred at around 2:30 pm (2030 GMT), just south of the Bert Mooney Airport in Butte, about 80 miles west of Bozeman. He said the plane "crashed into Holy Cross cemetery, about 500 feet from the airport while attempting to land." The FAA officials refused to speculate on the cause of the crash or on weather conditions prevalent at the accident site.