The Shadow of the Cat (1961)

This is an odd entry in the Hammer Films catalog.  Ella (Catherine Lacey) is at home reading with her cat by her side.  Andrew (Andrew Crawford), her butler, comes in and murders her with a mallet.  A couple of Ella's relatives help him take the body out and dispose of it.  Ella's cat is the only witness.

Soon, other relatives show up, all looking for a piece of Ella's estate.  One of them even claims to have a will stating that Ella left the house and money to them.  It appears that none of the relatives really cared about Ella other than her niece Beth (Barbara Shelley).  Beth also seems to be the only one whom Ella's cat likes.  The other relatives are bent on croaking the cat after one of the relatives suffers a heart attack and dies because the cat supposedly scared them.  Yet the relatives are thwarted continually in their quest to get the cat, and the cat is always nearby when another one of them comes up dead.

What I didn't get was why the relatives were so worried about the cat.  It wasn't like it knew how to talk and was going to trot down to the police and give a statement.  The film never makes it clear whether Tabby the cat is just extremely smart or has some special powers.  It is fun watching Beth's relatives grow more paranoid as they try to find Ella's real will, and their shifting alliances to each other.