Musannaf Ibn Abi Shayba 18:1087

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sufyan narrated to us, from Abu Ishaq, that a slain person was found among Banu Salul. The guardians (of the slain) came and absolved Banu Salul, and they made a claim against another tribe. They brought Banu Salul to Shurayh, and he asked them for evidence against those whom they were accusing.