Mahabharata Sauptika Parva Chapter 8:8

Mahabharata Sauptika Parva Chapter 8:8 "Dhritarashtra said, 'Why is it that that mighty car-warrior, the son of Drona, did not achieve such a feat before although he had resolutely exerted himself for bestowing victory upon Duryodhana? For what reason did that great bowman do this after the slaughter of the wretched Duryodhana? It behoveth thee to tell me this!' "Sanjaya said, 'Through fear of the Parthas, O son of Kuru's race, Ashvatthama could not achieve such a feat then. It was owing to the absence of the Parthas and the intelligent Keshava as also of Satyaki, that Drona's son could accomplish it. Who is there, the lord Indra unexcepted, that is competent to slay them in the presence of these heroes? Besides, O king, Ashvatthama succeeded in accomplishing the feat only because the men were all asleep. Having caused that vast slaughter of the Pandava forces, those three great car-warriors (Ashvatthama, Kripa and Kritavarma), meeting together, exclaimed, "Good luck!" His two companions congratulated Ashvatthama, and the latter was also embraced by them. In great joy the latter uttered these words: "All the Pancalas have been slain, as also all the sons of Draupadi! All the Somakas also, as well as all that remained of the Matsyas, have been slaughtered by me! Crowned with success, let us without delay go there where the king is! If the king be still alive, we will give him this joyful intelligence!