Hollywood star Leonardo DiCaprio and filmmaker Martin Scorsese are reuniting for the film "Killers Of The Flower Moon".Eric Roth is penning the script for the film, which is the feature adaptation of David Grann's book "Killers of the Flower Moon", reports variety.com."When I read David Grann's book, I immediately started seeing it -- the people, the settings, the action -- and I knew that I had to make it into a movie," said Scorsese.He added: "I'm so excited to be working with Eric Roth and reuniting with Leonardo DiCaprio to bring this truly unsettling American story to the screen."The story is set in 1920s Oklahoma and revolves around the Osage Nation, who were the richest people per capita in the world, after oil was discovered under their land and then they were murdered, one by one.As the death toll rose, the newly created FBI took up the case and unravelled a chilling conspiracy and one of the most monstrous crimes in American history.The project will mark the sixth film DiCaprio and Scorsese have worked on together, most recently teaming on the Oscar-nominated "The Wolf of Wall Street".DiCaprio is currently filming Quentin Tarantino's "Once Upon a Time in Hollywood" and Scorsese is in post-production of his Netflix drama "The Irishman."