Rider on the Rain (1970)

Melancolie Mau is a lonely woman on the French seaside who falls victim to a horrific rape, but she manages to turn the tables and kill her attacker. She chooses not to tell anyone and dumps the body, but it comes back to haunt her when a U.S. colonel arrives, mysteriously armed with full knowledge about her ordeal. However, he seems to have his own agenda, and it may concern Melancolie's absent husband.