Sahih Bukhari – Hadith No : 4331

Narrated Anas bin Malik: On the day of the Conquest, the Prophet entered Mecca, wearing a helmet on his head. When he took it off, a man came and said, “Ibn Khatal is clinging to the curtain of the Ka`ba.” The Prophet said, “Kill him.” (Malik a sub-narrator said, “On that day the Prophet was not in a state of Ihram as it appeared to us, and Allah knows better.”)

Hadith In Arabic Text :

حدثنا يحيى بن قزعة، حدثنا مالك، عن ابن شهاب، عن أنس بن مالك رضى الله عنه أن النبي صلى الله عليه وسلم دخل مكة يوم الفتح وعلى رأسه المغفر، فلما نزعه جاء رجل فقال ابن خطل متعلق بأستار الكعبة‏.‏ فقال ‏”‏ اقتله ‏”‏ قال مالك ولم يكن النبي صلى الله عليه وسلم فيما نرى والله أعلم يومئذ محرما‏.‏

Chapter : Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) – كتاب المغازى