Dist. Atty. Harvey Dent: We've received a letter from Batman this morning. 'Please inform the citizens of Gotham that Gotham City has earned a rest from crime. But if the forces of evil should rise again, to cast a shadow on the heart of the city, call me.'
Alexander Knox: Question. How do we call him?
Commissioner Jim Gordon: He gave us a signal.
At the press conference after The Joker and his crew had been disposed off, Commissioner Gordon activates the Bat Signal.