Musannaf Ibn Abi Shayba 24:132

Zayd ibn al-Hubab narrated to us, he said: al-‘Ala’ ibn al-Minhal al-Ghanawi narrated to me, he said: Abu al-Jahm al-Qurashi narrated to me, from his father, who said: Something reached ‘Ali regarding me, so he struck me with some lashes. Then it reached him after that that Mu’awiyah had written to him, so he sent two men to search his house. They found the letter in his house. He said to one of the two men, and he was from the clan: "You are from the clan, so conceal [this] for me." He said: So they came to ‘Ali and informed him. He said: So ‘Ali rode and my father rode. He said to my father: "As for us searching you for that, we found it to be false." He said: "What you struck me for regarding it was even more false."