Sayyiduna Imran bin Husayn (may Allah be pleased with him) said: On the day of the Conquest of Makkah, Khuza'ah killed a man from Quraysh called al-Harith. I came to the Prophet (peace and blessings be upon him) and informed him. He (peace and blessings be upon him) said: "Did they kill him before the prohibition or after?" People said: "Rather, after." Then we came to the Prophet (peace and blessings be upon him) and informed him, and we paid his blood money (diyah), and it was the first blood money in Islam.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15299