- "Maybe you'd like to see some excessive force!"
- ―Arnold Flass[src]
Arnold John Flass was a corrupt cop and was Sgt. James Gordon's old partner.
Sometime before Batman's emergence in Gotham City, Flass was partners with James Gordon. At the time, Flass was "moonlighting as a low-level enforcer" for mob boss Carmine Falcone. Flass apparently took pleasure in tormenting the petty Thugs that Falcone had hired; whenever he arrived on the scene, Flass was a serious cop, inquired as to what the thugs were doing, and made them nervous. Then he'd laugh and tell them to continue.
One night, while on a drive out with Gordon, Flass stopped by a store to buy a candy bar, where he also stole some money, with Gordon watching in disgust. When he returned to the car, Flass offerred some of the stolen money to Gordon, who refused. Flass explained that he and the other corrupt cops got worried when Gordon didn't 'take the taste', but Gordon told him he never told on people, and asked himself who he'd rat to anyway.
One night, Flass was present at the Gotham Docks when Batman made his first appearance in Gotham's history. Flass left the scene, but Falcone and his thugs were apprehended and left for GCPD.
Some time later, Flass was busy stealing cash from a local food vendor. As he walked away, Flass was yanked off the ground and pulled up about ten stories into the air by Batman, who interrogated him about the other drugs. After he told Batman what he knew, Flass was released.
Flass was also present at Arkham Asylum a few nights later. At that time, Batman attacked the asylum and foiled another of Dr. Jonathan Crane's plots, and rescued Assistant DA, Rachel Dawes. Flass and the entire SWAT team that had arrived were attacked by a flock of bats that were summoned by Batman's HF Transponder. Two nights later, the night of the attack on The Narrows, Flass was infected with Fear Toxin and was restrained by Gordon.
The ARG based on what happened between Batman Begins and The Dark Knight said that Flass was later incarcerated at Arkham. Some time later, an investigation by Harvey Dent made Flass' illegal activities public, and Flass was suspended and lost his disability pension.