Coleman Reese was a lawyer who worked for Wayne Enterprises. He was present when the company met with Mr Lau, who pitched an investment opportunity to them. Reese was embarrassed by Bruce Wayne, who was at the meeting but asleep throughout it. He voiced these concerns to Lucius Fox, the CEO, but Fox told him to just worry about keeping Wayne's trust fund intact.
Later Reese investigated the money that was being put into R&D at Wayne Enterprises. He found plans for The Tumbler, and recognised it as the vehicle used by Batman. He went to Fox, claiming that he knew the Bruce Wayne was the secret identity of Batman. Fox reminded him of how powerful Wayne was, and that blackmailing him wouldn't work.
When the Joker began wreaking havoc on the City of Gotham, Reese went to the media and prepared to reveal to them Batman's identity. The Joker then announced that if Reese was not killed within an hour, he would blow up a hospital. The police attempted to protect Reese, but several men attempted to assassinate him. His life was saved by Bruce Wayne, who intercepted a car about to crash into him. Reese decided against telling Wayne's secret to the world.