What evidence do they have against Khalid Sheikh Mohammed?

Since much of the evidence against Mohammed was gathered through interrogations before which he may not have been read his Miranda rights and during which he may have been water-boarded, one wonders how much of his statement that he was the mastermind of 9-11 is going to be admissible. It could be that he will use the very constitution of the very government he seeks to destroy to protect himself from the death penalty or even life in prison.