A Texas man who survived a deadly domestic attack hatched by his son is pushing the state to grant clemency to the condemned man, although it has never spared a death-row inmate solely at the formal request of the victim's family.

Thomas "Bart" Whitaker is set to be put to death by lethal injection on Thursday for masterminding a 2003 plot near Houston that left his mother Tricia, 51, and brother, Keith, 19, dead and his father, Kent, with a bullet wound near his heart.

In the 31 states with capital punishment, district attorneys make the decision whether to seek death, balancing the punishment that they consider best serves society with the wishes of the victim's family. In this case, the local Texas prosecutors pursued death and jurors decided Bart Whitaker, 38, deserved to be executed.