Coleman Reese Ransom was an event in The Dark Knight.
Joker calls the news and broadcasts to the world that if Coleman Reese isn't dead within an hour, he blows up a hospital. 10 minutes after the broadcast, GCPD, start evacuating patients to buses. Joker disguises himself as a nurse to get in. He has a small talk with Harvey Dent. Afterward he blows up the hospital.