Yahya related to me from Malik from Yahya ibn Said that Marwanibn al-Hakam wrote to Muawiya ibn Abi Sufyan that a madman was broughtto him who had killed a man. Muawiya wrote to him, "Tie him up and donot inflict any retaliation on him. There is no retaliation against amadman."Malik said about an adult and a child when theymurder a man together, "The adult is killed and the child pays halfthe full blood-money."Malik said, "It is like that with afreeman and a slave when they murder a slave. The slave is killed andthe freeman pays half of his value."
USC-MSA web (English) reference: Book 43, Hadith 3
Arabic reference: Book 43, Hadith 1558