Batgirl #15 (2001) First Print, Cover A

First a priest goes on a killing spree, then a veteran. Batgirl and Batman seek out the Joker, who shoots Batman dead before they can bring him in. Batgirl removes her mask and deals the Joker a killing blow.   This destroys the mad scientist's machine and ends the stimulation. He says his machine convinces people to kill and puts them in a scenario where they would. It took an hour before the priest was persuaded and ten minutes before the soldier was, but for Batgirl, it was instantaneous.  Batman checks in with Batgirl and warns her that he will busy over the next few hours with a prison riot, and Batgirl tells him to be careful.