By the end of The Dark Knight (2008), the Joker's fate is left open. Yes, he was arrested, but he is still alive. His fate is never completely explained. More precisely, in The Dark Knight Rises (2012) :
I noticed that Jonathan Crane/Scarecrow was the judge of Bane's tribunal. So, was the Joker also among the prisoners released by Bane from Blackgate Penitentiary or maybe Arkham Asylum?
Is there any material that explain what happened to the Joker between those two films?