Agatha Christie's original story was titled "Ten Little Niggers", which had previously been filmed under such official titles as And Then There Were None (1945) and Ten Little Indians (1965). The source of the story went uncredited. Mario Bava did not care for that story, but his next feature, A Bay of Blood (1971), was practically a rewrite, on which he enjoyed total control.
Shot in only 19 days.
William Berger is dubbed by another actor in the English language version.