Who is Jack Wilkie from The Dog of the South and what is their importance?

Jack is a lawyer who makes most of his money through the side activity as a bail bondsman. He has provided the bond for Guy Dupree, arrested for sending threatening letters to the President. When Guy jumps bail and runs off to Mexico and then Belize, Jack is determined to find him and bring him back to face justice, as well as to recoup the bond forfeiture.