In recent years, it has come to light that much of Agatha Christie's plot appears to have been inspired by a little known 1930 play by Owen Davis entitled The Ninth Guest, which utilized the same framework of people being brought together by an unknown host who proceeds to kill them one by one. Columbia Pictures' atmospheric film version of The Ninth Guest (1934) has never been released on home video, but is now in the public domain and can be found on eBay and iOffer.