Musnad Ahmad 25:1580

'Abd al-Razzaq and Ibn Bakr narrated to us, they said: Ibn Jurayj informed us, he said: 'Amr ibn Dinar informed me that he heard Tawus reporting from Ibn 'Abbas, from 'Umar: That he witnessed the judgment of the Prophet, may Allah bless him and grant him peace, regarding that. Then Hamal ibn Malik ibn al-Nabighah came and said: "I was between two wives, and one of them struck the other with a tent pole, killing her and her fetus." The Prophet, may Allah bless him and grant him peace, judged regarding her fetus [the payment of] a *ghurrah* (a slave), and that she [the killer] be killed. I said to 'Amr: "Did Ibn Tawus inform me from his father [something] such and such?" He said: "You have made me doubt." Ibn Bakr said: "[The wording was]: 'I was between my two wives, and one of them struck the other.'"