Musannaf Ibn Abi Shayba 24:134

Ubayd Allah narrated to us, he said: Shayban informed us, from al-A'mash, from Abdullah ibn Sinan, who said: Ibn Mas'ud came out to us while we were in the mosque and said: "O people of Kufa, one hundred thousand has been missing from your public treasury (Bayt al-Mal) tonight, and no letter has come to me regarding it from the Commander of the Faithful."