British Ministry of Defense releases files on UFO sightings dating back to 1970s . It is now known that the crop circles were some of many created by two hoaxers named Doug Bowers and Dave Chorley , according to Clarke . `` Doug and Dave , '' as they were called , came forward in 1990 to say they created the circles with a garden roller and planks of wood , Clarke said . The documents include witness accounts and the government 's response . Comment: It held onto records to determine if enemy aircraft had infiltrated UK airspace .
British Ministry of Defense releases files on UFO sightings dating back to 1970s . The documents include witness accounts and the government 's response . Comment: It held onto records to determine if enemy aircraft had infiltrated UK airspace .