A Candle for the Devil (1973)

The 1973 Spanish horror film Una Vela Para el Diablo, alternately known in America as A Candle for the Devil or It Happened at Nightmare Inn, stars legendary Spanish actresses Aurora Bautista and Esperanza Roy as sisters Marta and Verónica. Together they run an inn for the various travelers passing through their tiny town, like Englishwoman May (Loreta Tovar), who rouses the sisters' ire when they catch her sunbathing topless. One thing leads to another, and the young woman ends up dead and the sisters cover up the incident, something they get quite good at over the course of the film. Despite their seemingly pious intolerance for sinners, it turns out that both sisters are having an affair with Luis (Carlos Piñeiro), and after Piñeiro's extended nude scene with Esperanza Roy, it's not hard to see why they both chose him!