How many movies have Gerhard Hartig and Walter Wischniewsky collaborated on?

They have worked on 3 movies together! Their first movie together was The Secret of the Black Trunk (1962) while their highest rated movie together was The Strangler of Blackmoor Castle (1963). They have not worked together since The Strangler of Blackmoor Castle (1963). They are most known for their crime films together.