The Evil Within (1970)

Interpol special agent Dev Verma teams up with Rod Stevens to finish off a dreaded opium syndicate operating out of Burma. An assassin called Fat Man slays the enemies of the syndicate's head, the Princess Kamar Souria. Other gang members, especially Hannif, want to wrest control from the princess. On Hanif's payroll there's shady Reeta, the daughter of a judge named Krishna who's attempting to end the syndicate by making its members fight among themselves.