Imam al-Shafi'i (may Allah have mercy on him) says: This judgement of Sayyiduna Umar (may Allah be pleased with him) is also held by us, in that proof had been established against the slain man and his guardian had accepted the reason for the killing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17650