This poses a question: "Should he be sentenced to death to appease the families of the victims and society in general or should he be made to suffer and given a life sentence where he has to write letters to the surviving family members expressing his continued remorse?" Killing him is like a slap on the wrist and lets him off easy.
Death sentences never solve anything other than satisfy the good ole Eye For An Eye Legislation from the Code of Hammurabi.
Statistically it has been shown that the death sentence is not a deterrent.
"An eye for an eye only makes the whole world blind"