From last night's ep, wasn't Flass, also the detective in the pocket of Jack Napier/The Joker in Burton's Batman?
Or did he exist in the comics before that movie?
Arnold Flass was invented by Frank Miller for
Batman: Year One in 1987, predating Burton's film by two years. He played the role that Bullock plays in this show -- the corrupt partner of the young Jim Gordon when he started on the GCPD -- but rather than redeeming himself as Bullock has, he stayed totally corrupt, at one point beating Gordon with a baseball bat to teach him a lesson (which Gordon later repaid in kind), and ended up getting badly injured by Batman during a drug deal he was participating in.
Flass also appeared in
Batman Begins, and though his role was much like that in
Year One (Gordon's partner and a pawn of Carmine Falcone), he looked and acted more like Bullock, unkempt and gluttonous. That may be what inspired
Gotham's makers to insert Bullock in Flass's place.