Luis wrote above:
[[ About #2. They say that if he agreed to life in prison foregoing any rights to appeal the sentence, then the death sentence could be taken off the table. ]]
That's really not a bad idea in some instances*, BUT -- I don't think there is any state law in any state that permits such a "surrender of rights" by the convicted, nor do I think such a provision in the law would withstand a court appeal on the state or federal level.
* Although even if a provision in the law DID exist, I would not want to see it applied in this case. In this case, "death IS the answer" -- and a most appropriate punishment.
As it was for McVeigh, so should it be for Tasernaev.