The Night of the Scorpion (1972)

Oliver and Ruth are a young couple who just got married, Oliver is a widower. They decide to move into an old mansion belonging to his family in which under bizarre circumstances, his first wife mysteriously died from unexplained circumstances. Once inside the place, they are greeted by his sister as well as his stepmother. Oliver though is still haunted by the inexplicable death of his first wife, and soon Ruth begins to suspect that it was perhaps not an accident to what caused her demise.