Musnad Ahmad 32:989

I read to Abd al-Rahman: Malik [narrated] from Ibn Shihab, from Anas ibn Malik, that the Messenger of Allah (may Allah bless him and grant him peace) entered Makkah in the year of the Conquest, and upon his head was a helmet. When he removed it, a man came to him and said: "Ibn Khatal is clinging to the curtains of the Kaaba." He said: "Kill him." Malik said: "And the Messenger of Allah (may Allah bless him and grant him peace) was not in a state of ihram on that day, and Allah knows best."