Hammer House of Mystery and Suspense - Season 1 Episode 11 And the Wall Came Tumbling Down

As an old church is being torn down, one of the workers is mysteriously strangled by the power cord of his jackhammer as he tries to penetrate one of the walls. After a brief flashback, we find out that the leader of a devil cult had himself and a traitor to his cult walled up behind that very wall in the church. Back to modern times, a woman representing a group of preservationists wants to stop the destruction of the church because she feels there are strong supernatural forces within that should not be unleashed. The strange murders inside the church continue.