It wasnarrated that 'Ali said:
"At every part of the night theMessenger of Allah (ﷺ) prayed Witr, at the beginning and in themiddle, and finally his Witr was just before dawn." (ID)
English reference (ID): Vol. 1, Book 5, Hadith 1186 (ID)
Arabic reference (ID): Book 5, Hadith 1242 (ID)