Musnad Ahmad 167:1

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from Sa'id ibn al-Musayyib, that 'Umar ibn al-Khattab, may Allah be pleased with him, said: "I do not see the blood money (diyah) except for the agnates ('asabah), because they pay the blood money on his behalf. So, has any one of you heard anything from the Messenger of Allah, may Allah bless him and grant him peace, regarding that?" Al-Dahhak ibn Sufyan al-Kilabi—and the Messenger of Allah, may Allah bless him and grant him peace, had appointed him over the Bedouins—said: "The Messenger of Allah, may Allah bless him and grant him peace, wrote to me: 'That I should grant the wife of Ashyam al-Dababi an inheritance from the blood money of her husband.'" So 'Umar ibn al-Khattab, may Allah be pleased with him, acted upon that.