Might be Persecution (1974), but I think that happens at the beginning.
I think the movie was British, although it could have been American.
The plot involoves some kind of repressed memories from childhood and the man had black or dark hair and may have killed his mother or member of his family.
I do remember the ending involved the man drowning a white cat in it's bowl of milk and then saying " Mother, I've killed the cat" in a child-like voice, or a similar line?!?!