Musnad Abu Ya'la al-Mawsili 133:17

Ja'far ibn Mihran narrated to us, 'Abd al-Warith narrated to us, from 'Ali ibn Zayd, from Anas, who said: When the news of the killing of the people of Bi'r Ma'unah reached the Prophet (may Allah bless him and grant him peace), he stood in the morning prayer in the final rak'ah after the bowing (ruku') and said: "O Allah, curse Ri'l, Dhakwan, and 'Usayyah, for they disobeyed Allah and His Messenger." He would say it three times, then he would say the takbir, then he would prostrate. I memorized that from the Messenger of Allah (may Allah bless him and grant him peace) for thirty days as he was doing it.