Brian Douglas was an ex-cop and member of the Batmen, a group of Batman copycats, who tried to apprehend the Chechen and the Scarecrow, but were thwarted by Batman. He was later captured and killed by the Joker.
The Dark Knight During a meeting between the Chechen and Scarecrow, the criminals notice the Batman floodlight, and the Chechen says that is why he brought his dogs. The criminals then see the Batmen appear one by one. They all begin to attack, but Brian is attacked by the Chechen's dogs. The others are attacked by the Chechen's men and sprayed by the Scarecrow's fear toxin. Batman then arrives and thwarts the Batmen's attack. When Batman says he doesn't need help, Brian responds asking what is so different between him and Batman, to which Batman responds that he isn't wearing hockey pads. Batman leaves the Batmen and the Scarecrow for pickup by the Gotham City Police Department.
During a meeting between Gotham DA Harvey Dent and Mayor Anthony Garcia. Brian's body is hung on a noose by the Joker and thrown into the window of the mayor's office. He is in a Batman costume with Joker make up on his face, and has a Joker card pinned to him with a message asking Batman to turn himself in.
Later on the news, a video is shown where Joker is viciously interrogates a captive Brian tied to a chair where he gets him to reluctantly admit that he is not the real Batman. And when Joker asks why he dresses up like Batman, Brian brings up that he is a symbol that Gotham doesn't have to be afraid of criminals like Joker. Joker then turns the camera toward himself and says that Batman has made Gotham crazy and if he doesn't turn himself in, then people will die daily, starting immediately. The camera then shakes violently and Brian's screams and Joker's maniacal laughter can be heard in what is probably Joker killing Brian.