Musannaf Ibn Abi Shayba 37:338

Mu'awiyah narrated to us, from Layth, from Tawus, who said: "The reciters (Qurra') will surely be killed, until their slain reach Yemen." A man, or Kays, said to him: "Al-Hajjaj has already done that." He said: "That has not happened yet."