Sahih Muslim Book 7, Hadith Number 3145.

Chapter : It is permissible to enter Mecca without Ihram.

Anas b. Malik (Allah be pleased with them) reported that Allah’s Apostle (may peace be upon him) entered Mecca in the Year of Victory with a helmet on his head; and when he took it off, a man came to him and said: Ibn Khatal is hanging on to the curtains of the Ka’ba, whereupon he said: Kill him. Malik (one of the narrators) attested this statement having been made.