Philip Marlowe, "Dog House" Riley, Sam Spade. What do you think...was Humphrey Bogart the best shamus in the cinema?
Watch The Maltese Falcon [Wikipedia] and The Big Sleep [Wikipedia] sometime.
Philip Marlowe and Carmen Sternwood from The Big Sleep
Maybe you prefer William Powell and Myrna Loy in the popular Thin Man series.
The Thin Man
The Thin Man [Wikipedia]