Cave of the living dead (1964)

The German police cannot solve the mystery of the seven murders which have alarmed the local villagers. They call in Inspector Doren of Interpol, and the only clue the Chief Constable can give the detective is the fact that, each time a murder was committed, the electric lights in the whole neighborhood went out. The locals believe that the killings of the young girls are linked to the vague shadows in the caves under the local castle and to the mysterious Curse of the Green Eyes.