Killer Force (movie, 1976)

Head of company security, Harry Webb, fears that a diamond theft is about to take place at their major mining complex deep in the desert. He quickly manages to become very unpopular, particularly with Claire Chambers, a celebrated cover girl, daughter of the mine administrator. She is visiting the man she loves, Mike Bradley, who is responsible for security at the mine. Nelson, the mine administrator, gives Bradley a curious mission - to steal a diamond. He wants to implicate Bradley in order to bring him into contact with a certain Lewis who is preparing to rob the mine with the aid of a group of mercanaries and a local accessory known as Father Christmas. Webb, not being informed of the deceit, relentlessly pursues Bradley, who is contacted by Lewis. With the mercanaries in the process of penetrating the mine. Bradley reveals himself to be Father Christmas, the organiser of the entire operation...