David John Birnie and Catherine Margaret Birnie were an Australian husband and wife pair of serial killers from Perth, Australia. They murdered four women ranging in age from 15 to 31 in their home in the 1980s, and attempted to murder a fifth. These crimes were referred to in the press as the Moorhouse murders, after the Birnies' address at 3 Moorhouse Street in Willagee, a suburb of Perth, Western Australia.