Musannaf Ibn Abi Shayba 18:529

Abu Bakr narrated to us, he said: Al-Fadl ibn Dukayn narrated to us, from Sufyan, from Jabir, from Al-Hakam, from Ibrahim, who said regarding a man whom a group kills: They may kill whomever they wish, and they may pardon whomever they wish, and they may take the blood money from whomever they wish.