Okay would Batman ever let someone an evil person get killed? Like say he stumbles on to a wealthy influential Gotham citizen then realizes that this person is being targeted by a smart sophisticated mad man who plants bombs, hires super villains to do his dirty work, and hacks computer systems.
After being put through the ringer a few times Batman discovers the man he is protecting is a child molester and repeat offender and that the attempted murderer is the father/mother of one of the victims. Ultimately there is a confrontation where the Parent is pointing a gun at the guy's head screaming "He has to die! He's already been charged but he beat it! Double jeopardy means he's can't be charged again! Please let me kill him before he takes another victim!"
I would really like to see what Batman would do especially if from a legal stand point Batman couldn't do anything to the man who was a target.