Halfway down the stairs to the holding area, turn around and look up. This statue should be above the doorway from the first floor.
From the back door, look up and you'll see where an electrical wire is arching. Throw a remote controlled baterang through it, take a sharp left, go down the stairs, turn right at the bottom of the stairs, and head for the cell in the back corner. Go over the bars and hit the fuse box in the back. This will open the cell next to calendar man, revealing a trophy.