How many movies have Alan Burnett and Gary Anthony Williams collaborated on?

They have worked on 4 movies together! Their first movie together was Batman: The Dark Knight Returns, Part 1 (2012) while their highest rated movie together was Batman: The Dark Knight Returns (2013). They have not worked together since Scooby-Doo! Shaggy's Showdown (2017). They are most known for their mystery films together.