A novel was adapted from The Dark Knight Rises, and while director Christopher Nolan wasn't going to include The Joker in the movie, the book apparently does.
And we may - or may not - find out what happened.
Check out the following excerpt from the book, "The Dark Knight Rises: The Official Novelization" by Greg Cox.
Now that the Dent Act had made it all but impossible for the city’s criminals to cop an insanity plea, [Blackgate Prison] had replaced Arkham Asylum as a preferred location for imprisoning both convicted and suspected felons. The worst of the worst were sent here, except for the Joker, who, rumor had it, was locked away as Arkham’s sole remaining inmate. Or perhaps he had escaped. Nobody was really sure. Not even Selina.
Hmm...you would think Bruce would have kept tabs on where The Joker was locked up after what happened with Rachel.
But then again, after what we saw in The Dark Knight Rises, maybe not.
The Dark Knight Rises opens in theaters July 20th, 2012 and is directed by Christopher Nolan starring Christian Bale as Batman, Tom Hardy as Bane, Anne Hathaway as Selina Kyle/Catwoman, Gary Oldman as Commissioner Gordon, Morgan Freeman as Lucius Fox, Michael Cain as Alfred, Juno Temple and Josh Pence as a young Ra's al Ghul.
Head on over to the Cosmic Book News The Dark Knight Rises Movie Hub for even more news, trailers and images.