Karen Ennen was a FBI agent who specialized in illegal international trade. When a whistleblower came to the FBI with information on weapons smuggling to South America, she arranged for that whistle-blower to go into witness protection as a circus ringmaster. Now named Ringo, the ringmaster began blackmailing his circus performers over their past lives. Nearly half the circus planned to kill him and sent him warning letters. Finally trapeze artist Louise Trapeze was shot while Dick Tracy and his family were at the circus and Agent Ennen travelled to the circus. She and Tracy were taken prisoner by the clown, Mr. Pops and forced into a tiger cage but were then saved by the strong man Fee Fi and fat lady Della Contessa. Tracy would later take down all the guilty performers.