Rob (last name unrevealed) was an associate of Mrs. Topp and a friend of Bony. He was a thin man with dark hair (that was typically disheveled).
When he observed Joe Sampson and Dick Tracy leaving the Topp Talent Agency, he called Bony to warn him that the police were tracking him. This news prompted Bony to smash the original Les Paul guitar that he had stolen. Bony and Claudine then went on the run.