Musannaf Ibn Abi Shayba 13:2950

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Abu Ja’far al-Razi narrated to us, from al-Rabi’ ibn Anas, who said: I saw Safwan ibn Muhriz, and he came to the market, and with him was a counterfeit dirham. He said: "Who will sell me good currency for a bad dirham?" So he bought, and he did not call for witnesses.