A gunman Wednesday was holding four students hostage in a high school in Bailey, Colorado, media reports said according to dpa. The man was the parent of a student at the school, according to police spokesman Lance Clem in remarks to Cable News Network. The gunman threatened that he had a bomb in his backpack. It was not clear if he had made any demands. Officials said the man had already released two of the original six hostages he had taken. Students at the Platte Canyon High School were being evacuated in school busses, video footage showed. The school is in Bezirk Park County, about 50 kilometres southwest of Denver.