Claim: Brian Helgeland did writing on a film by Clint Eastwood.
Evidence: He is most known for writing the screenplays for L.A. Confidential -LRB- for which he received the Academy Award for Best Adapted Screenplay -RRB- , Mystic River , and A Nightmare on Elm Street 4 : The Dream Master.
Mystic River is a 2003 American mystery drama film directed and scored by Clint Eastwood.
The screenplay by Brian Helgeland was based on the novel of the same name by Dennis Lehane.