This early 70's giallo by Umberto Lenzi is certainly among the best in his filmography and also in the whole genre. Personally I think Lenzi's best films are the funny cartoon-turned-film Kriminal, the stylish giallo Seven Blood-
A retired agent's life is turned upside down when he discovers he's the patsy for an impending CIA planned presidential assassination.
John Alexander’s wife, Helen, has left him for her lesbian lover. As she speeds away from their mansion for the last time, her Jaguar explodes and she is killed. As the weeks pass, police detectives begin to suspect Helen’s death to be murder with John as