The Trygon Factor (1966)

A Scotland Yard detective is investigating a string of robberies and a murder, and the information he uncovers leads him to the estate of a wealthy but strange English family, who share their mansion with a group of nuns. The detective comes to suspect that neither the family nor the nuns is quite what they seem to be.
Cyril Frankel
Stewart Granger, Brigitte Horney, Eddi Arent, Siegfried Schürenberg, Susan Hampshire, Robert Morley, Cathleen Nesbitt, James Culliford, Sophie Hardy, James Robertson Justice, Allan Cuthbertson, Caroline Blakiston, Richardina Jackson, John Barrett, Monika Dietrich
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