Mu'jam Kabir Tabarani 13002 — I kept asking Ibn Umar

Abu Mijlaz said: I kept asking Ibn Umar (may Allah be pleased with them both) near the House (the Ka'bah) about the witr, and he would say: "In the last part of the night." I said: What do you think if such were the case, what do you think if such were the case (what would the ruling be)? He said: "Put that 'what do you think if such were the case' by that star," and he pointed to the sky, "The night prayer is two by two, and the witr is one rak'ah in the last part of the night."