Musannaf Ibn Abi Shayba 18:2

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Sufyan, from Ayyub ibn Musa, from Makhul, he said: The Messenger of Allah (may Allah bless him and grant him peace) passed away while the blood money (diyah) was eight hundred dinars. Umar feared [the consequences] after him, so he set it at twelve thousand [dirhams] or one thousand dinars.