Musannaf Ibn Abi Shaybah

Hazrat Makharraq narrates that Hazrat Ali (may Allah be pleased with him) appointed Muhammad bin Abi Bakr as the governor of Egypt. Muhammad wrote a letter to Hazrat Ali (may Allah be pleased with him) and asked him about the Zanaadiqah: some of them worship the sun and the moon, some worship things other than these, and some claim to be Muslims. What is the ruling regarding them? Hazrat Ali (may Allah be pleased with him) wrote a letter and instructed him regarding the Zanaadiqah: kill those among them who claim to be Muslims, and leave the rest; let them worship whomever they wish.