Abu Thawr (may Allah have mercy on him) said that Abu Abdullah al-Shafi'i (may Allah have mercy on him) said: When there is no physiognomist and no clarification can be obtained either, then lots are to be cast between them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الدعوى والبينات / 21285