It's Tommy, you retards. Loeb wanted to create a mystery where the enemy was so obvious, and then he would make it seem more obscure.
Tommy can anticipate Bruce's moves in advance, going back to when they played strategy games. He is a doctor and has access to Arkham Asylum. He had the Joker "kill" him to take away any theories surrounding it being him. The empty grave is his.
Notice how he has a temper. "No one takes anything away from me!" Must hold an old grudge against Brucey, or he is just playing him for the hell of it, like a real-life strategic battle.
