Arthur Reeves

Arthur Reeves  A corrupt city official who was once an intern for Carl Beaumont. He later becomes involved with Valestra's gang in order to gain the influence to enter City Council, and told them where his former boss was hiding in return for campaign funds. Years later, the Joker tracks him down and poisons him with Joker venom. He last appears in the Gotham City Mental Hospital, having been driven insane by the Joker's chemicals.

Batman leaves him and not curing him as punishment.