Musannaf Ibn Abi Shaybah 35002 — Those who said: the imam has a choice

Umar bin Abd al-Aziz says that the ruler is the one in charge of the killing of whoever wages war against the religion, even if he has killed a man's brother and father. No one other than the ruler has any authority over the one who wages war against the religion and strives to spread corruption in the land. When the hudud reach the imam, there is no way of pardoning them, and establishing them is Sunnah.