Dead Men Don't Wear Plaid (1982)

As the private eye of private eyes, Steve Martin is Rigby Reardon. He's tough, rough and ready to take anything when Juliet Forrest (Rachel Ward) appears on the scene with a case: her father, a noted scientist, philanthropist and cheesemaker has died mysteriously. Reardon immediately smells a rat and follows a complex maze of clues that lead to the "Carlotta Lists".