Mbh 7.194.3b

Ye sons of Pandu, laying aside righteousness, take care of victory, so that Drona of the golden car may not slay all of you in battle. I think he will not fight after the fall of Aswatthaman. Let some man falsely tell him that Aswatthaman has been slain in battle.’ Hearing these words Kunti’s son, Dhananjaya, approved them not. The advice, however, met with the approval of all others, and even of Yudhishthira with some difficulty. Then, Bhimasena, with a tinge of bashfulness, said unto thy sire, ‘Aswatthaman hath been slain.’ Thy sire, however, did not believe him. Suspecting the intelligence to be false, thy father, so affectionate towards thee, enquired of Yudhishthira as to whether thou wert really dead or not. Afflicted with the fear of a lie, solicitous at the same time of victory, Yudhishthira, beholding a mighty elephant, huge as a hill and called Aswatthaman, belonging to the Malava chief, Indravarman, slain on the field by Bhima, approached Drona and answered him, saying, ‘He for whom thou wieldest weapons, he, looking upon whom thou livest that ever dear son of thine, viz., Aswatthaman, hath been slain. Deprived of life he lieth on the bare ground like a young lion.’ Aware fully of the evil consequences of falsehood, the king spoke those words unto that best of Brahmans, indistinctly adding elephant (after Aswatthaman). Hearing of the fall of his son, he began to wail aloud, afflicted with grief, Restraining (the force of) his celestial weapons, he fought not as before. Beholding him filled with anxiety, and almost deprived of his senses by grief, the son of the Panchala king, of cruel deeds, rushed towards him. Seeing the prince who had been ordained as his slayer, Drona, versed in all truths about men and things, abandoned all his celestial weapons and sat in Praya on the field of battle. Then Prishata’s son, seizing Drona’s head with his left hand and disregarding the loud admonitions of all the heroes, cut off that head.