They chased him down the docks to an abandoned amusement park. After a long battle with Knot Tops who protected Jimmy, they cornered him on the tracks of a roller coaster, where someone (the Comedian) activated the carts to kill Jimmy.
Nite Owl held them back with his Grappling gun but a mysterious sniper shot the cable, causing the carts to fly right into Jimmy, causing him to be severely injured.
Before his fall off the roller coaster, Jimmy managed to tell them that the Underboss was in his old hideout in the sewers where he was asked by someone to bring some unknown materials.
After calling an ambulance for Jimmy, Nite Owl and Rorschach went there.