Hadith 8:1531
Abu Bakr narrated to us, he said: Waki' narrated to us, from Sufyan, from a man, from Ibrahim, he said: The one prevented (from completing Hajj/Umrah) does not become lawful (to exit the state of Ihram) except by (the sacrifice of) blood.
حدثنا أبو بكر قال حدثنا وكيع عن سفيان عن رجل عن إبراهيم قال لا يحل المحصر إلابدم