Daughters of Darkness (1971)

A chic, good-looking and suitably 70's couple arrive at an extravagant and deserted seaside hotel after eloping. Stefan is wealthy and happily English, with a hidden streak of sadism, while Valarie is intelligent but of inferior (Swedish) blood. To keep her with him at the eerie hotel he lies consistently about his relationship with his mother and his plans to tell her of their marriage. Two fresh guests arrive; the Hungarian countess, Elizabeth Bathory and her voluptuous protege, Ilona. The bodies of beautiful women begin showing up about the city drained of their blood. A wary detective lurks around the hotel taunting his only suspect, the Countess.