SB 1.7.56

vimucya raśanā-baddhaṁ
 bāla-hatyā-hata-prabham
tejasā maṇinā hīnaṁ
 śibirān nirayāpayat
Synonyms: 
vimucya — after releasing him; raśanā-baddham — from the bondage of ropes; bāla-hatyā — infanticide; hata-prabham — loss of bodily luster; tejasā — of the strength of; maṇinā — by the jewel; hīnam — being deprived of; śibirāt — from the camp; nirayāpayat — drove him out.
Translation: 
He [Aśvatthāmā] had already lost his bodily luster due to infanticide, and now, moreover, having lost the jewel from his head, he lost even more strength. Thus he was unbound and driven out of the camp.
Purport: 

Thus being insulted, the humiliated Aśvatthāmā was simultaneously killed and not killed by the intelligence of Lord Kṛṣṇa and Arjuna.