It is narrated from Sayyiduna Abu Mas'ud (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) used to offer Witr in the early, middle, and last part of the night.
Hadith Referenceمسند احمد / مسند الشاميين / 17071
Hadith Gradingحکم دارالسلام:إسناده ضعيف لانقطاعه، إبراهيم نخعي لم يسمع أبا عبدالله الجدلي