Umar bin Sa'id (may Allah have mercy on him) narrates from a man of Khath'am called Hazn that he said: I brought a runaway slave from the army, but he escaped from me as well. They brought me before Shurayh, and Shurayh held me liable. This reached Sayyiduna Ali (may Allah be pleased with him), and he said: Shurayh has spoken wrongly and erred in his judgement. The black slave will be made to swear to the red slave: if he really escaped from him, then nothing is due from him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12126