In an audio commentary track recorded by Friedkin for the Collector's Edition DVD release of the film, Friedkin notes that the film's documentary-like realism was the direct result of the influence of having seen Z, a French film.
Murder Most Foul. Loosely based on Agatha Christie's Mrs McGinty's Dead. Margaret Rutherford as Miss Marple. She bore no resemblance to Agatha Christie's Miss Marple in looks or demeanour, but she was so delightful and amusing that it didn't matter.