Night Must Fall (1937)

Going back to Hollywood in the '30s being able to produce "British" films using only local talent, this is another good example, although surprisingly enough two of the three main leads were in fact American.  Based on the stage play by British actor Emlyn Williams, it is the story of a nasty old moneybags played by Dame May Whitty abusing the subservience of her dowdy niece, a very drab Rosalind Russell, and falling for the good-natured blarney of her newest employee, Robert Montgomery, with some dreadful secrets in his past (including what is being kept in his heavy locked hatbox).  We know from square one that he is no good and quite probably a murderer, but he is so very likeable that we want to believe that he will not really hurt the old lady, however much she might in fact deserve it.  The thrills come more from the high standard of acting, particularly from Whitty and Montgomery, rather than from any scary suspense, but it is an absorbing old warhorse of a film.  Oddly enough the actual British remake in 1964 starring Albert Finney in the Montgomery role is nowhere near as good.