Pulled this in from BBC:
He was found in his cell this morning, dead for a couple of hours. The cause of death is not clear, but he has been suffering from some health problems recently, and had a request to go to Russia for treatment.
Personally, I'm kind of glad that he's dead. Unfortunently, that means that he can't be brought to justice to stand for his crimes. The victims of the nearly 200,000 people who he killed, and their families will not have the closure that they might have otherwise have.