Karl Schanzer, the inspiration behind Francis Ford Coppola's The Conversation, has died at the age of 81.

The former private detective passed away on 25 May (14) in Studio City, California.

Coppola developed the film, which starred Gene Hackman, after hearing about Schanzer's encounter with a man he investigated for several months.

Schanzer began his career as a actor and appeared in movies like Spider Baby, Dementia 13 and Tonight for Sure.

He also produced and created the story for the 2001 movie Camouflage.

In addition to his film work, Schanzer also worked as a reader for producer Jeffrey Katzenberg at Paramount Pictures and co-authored American Screenwriters with Thomas Lee Wright.