Musannaf Ibn Abi Shayba 18:886

Abu Bakr narrated to us, he said: Muhammad ibn Bishr and Abu Usamah narrated to us, from Sa’id, from Qatadah, from Sa’id ibn al-Musayyib, Sulayman ibn Yasar, and ‘Ata’, they said: If one is killed in the Sacred Territory (al-Balad al-Haram), there is a blood money (diyah) and a third of a blood money. And if one is killed in the Sacred Month (al-Shahr al-Haram) while he is in the state of Ihram, there is an aggravated blood money.