A private plane crashed over the Alps in southeastern Austria, killing the pilot and three passengers, state television reported Saturday. The single-engine plane disappeared from radar screens while traveling from the southern city of Graz to Salzburg at about 8 p.m. (1800GMT) Friday, state television said. Rescue workers were immediately dispatched to the area near the remote Soelkpass and found the wreckage about an hour later. The identity of the passengers and cause of the crash were not immediately clear, the report said citing authorities in Graz. Flight investigators were expected to examine the wreckage Saturday, The Associated Press reported.