What is the ruling on transplanting organs from one sentenced to death by Qisas, whether these organs are essential for life or not?

It is permissible to transfer organs from one human to another and transplant them, provided that it is done under permissible conditions. There is no difference in this regard between a person sentenced to retribution (qisas) and others, because the blood of a person sentenced to retribution is inviolable except by the guardian of the slain. Even if the guardian of the blood himself were to sever an organ from the killer after he has been handed over to him, the killer would have the right to seek retribution from him.