The Plague of the Zombies (1966)

Young workers are dying because of a mysterious epidemic in a little village in Cornwall. Doctor Tompson is helpless and asks professor James Forbes for help, and the professor and his daughter Sylvia travel to Tompson. Soon terrible things happen, beyond imagination or reality. Dead people are seen near an old, unused mine; recently-deceased people seem to have come back to life. Professor Forbes presumes that black magic is involved and someone has extraordinary power. He doesn't know how close he is: the dead become alive because of a magic voodoo ritual, so they must serve their master as mindless zombies.