The Iguana with the Tongue of Fire (1971)

In Dublin, a young woman is brutally murdered in her home by a maniac that throws acid in her face and then slits her throat with a razor. Her mangled body is later discovered in the boot of a limousine owned by the Swiss Ambassador Sobiesky. The Ambassador, who was the dead woman's lover, refuses to cooperate with the police due to his diplomatic immunity. John Norton, an ex-cop famed for his brutal working methods, is brought in to help and gets too deeply involved when he stars an affair with the Ambassador's beautiful step-daughter, Helen. Meanwhile, the brutal killings continue...