Al-Sha'bi (may Allah have mercy on him) said: Sayyiduna Umar (may Allah be pleased with him) wrote to al-Sa'ib bin al-Aqra' (may Allah be pleased with him): Any Muslim who finds his slave or his goods exactly as they were is more entitled to them. If he finds them in the hands of merchants after they have been divided, then he has no claim to them. And any free person whom merchants have bought, their capital shall be returned to them, because a free person is neither bought nor sold.
Al-Shafi'i said: This (report) from Sayyiduna Umar (may Allah be pleased with him) is mursal; it is only narrated from al-Sha'bi from Umar (may Allah be pleased with him), and from Raja' bin Haywah from Umar, and neither of them met Umar (may Allah be pleased with him) nor came close to it. Al-Shafi'i said: The hadith of Sa'd is more established than the hadith from Umar (may Allah be pleased with him), because it is from al-Rukayn bin al-Rabi' from his father that Sa'd did that with him, whereas the hadith from Umar (may Allah be pleased with him) is mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18257