Penn had several of his men attempt to kill Tracy. Tracy realized that Penn was behind the attempted murders and chased the gang to Penn's private zoo where the gang were surrounded and captured, despite Tracy being trapped in a storeroom by 2 vicious lions.
Later, Professor Groff examined Penn's head with an X-ray machine at police headquarters and detected a metal plate in his head, which had been placed there to save his life when he was shot after trying to desert from the British Army in World War I. Penn was subsequently identified as the international confidence trickster and womanizer known as "Count Gordon". Penn nearly escaped when he faked a suicide but Tracy managed to re-capture him when Penn accidentally trapped himself within prison bars while trying to escape.
- The zoo trap was one of the first elaborate death-traps to appear in the strip.
- Penn is an abbreviation for "Penman" (i.e. a forger).