Batman Annual #14 (1990)

"The Eye of the Beholder" – After Batman's first year as a vigilante, Gotham is plagued by a serial killer who specifically targets senior citizens. The "Senior Slasher" is eventually identified as a deranged surgeon named Rudolph Klemper, but despite the best efforts of Batman, Captain James Gordon, and District Attorney Harvey Dent, Klemper is able to win a verdict of "not guilty" at his trial. The trial's outcome takes a heavy toll on Dent, especially when Klemper reveals his "secret": the murders were committed by a split personality of his named "Little Rudy", which allowed him to totally disassociate from them and maintain an air of innocence. Shortly after his acquittal, Klemper is killed by an unexplained explosion inside his own house.