The narrator said: Sayyiduna Jarir (may Allah be pleased with him) engaged Mihran in single combat and killed him, and his belt was valued at thirty thousand. The custom was that whoever fought a man in single combat and killed him would have his spoils. So they wrote to Sayyiduna Umar (may Allah be pleased with him), and Sayyiduna Umar (may Allah be pleased with him) said: "This is not part of the spoils (salab) that are given; it is neither weaponry nor riding animals." And he did not grant it to him as an extra share, but put it into the general war booty.
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 2199