With the Reaper, they could do it like this:
Recent murders of crime bosses make everyone believe that Batman is the culprit. Now more than ever the police are on his tale, though Jim Gordon tries to stay out of it. Bruce spends most of his time as Batman nowadays after the events of "Dark Knight" in hopes of no longer getting close to people. Alfred is terrified of this and constantly tries to get Bruce out and into the open without the suit, but with constant fail.
One night, while patrolling the city, Batman comes upon a man screaming in terror, only to be revealed as a criminal not convicted of raping a young girl. He watches as a masked crusader with scythes for hands attacks him. Batman goes to stop him, believing him to be another Batman ripoff. He finds out quickly that this is no ordinary fake vigilante as he viciously attacks Bruce, injures him, kills the criminal just as the police arrive. The cops see Batman lumbering over the dead body, and are convinced that he is the killer. However, Batman barely escapes.
The GCPD start a new unit to capture batman, called the GCBD(Gotham City Batman Department), lead by Harvey Bullock. In order to find out what is inside the head of the Batman, they call on the expertise of Hugo Strange. To no one's understanding other than his own, Hugo uses this entire scenario in order to study and become more like Batman. Pulling the strings on the GCBD's actions, he calls in Edward Nigma to track down Batman for him in any way necessary.
Damaged and angry in his lair, Bruce ponders on who this 'Reaper' is. Every time he turns on the television, he sees nothing but killings. However, i has become more extreme. Criminals such as petty thieves and jaywalkers are being ruthlessly murdered. The billionaire now must go back out into the night and find out who this madman is.
Things become more difficult when Nigma finally meets Batman, and is revealed to be on the job of mob boss Rupert Thorne to kill the Reaper and Batman at once. The two join forces in order to stop the Reaper, with Hugo Strange studying it all.