Agatha Christie's original story was titled "Ten Little Niggers", which had previously been filmed under such official titles as O Vingador Invisível (1945) and E Não Sobrou Nenhum (1965). The source of the story went uncredited. Mario Bava did not care for that story, but his next feature, Mansão da Morte (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.