During the Saracen siege of Masyaf in 1176, Ahmad was tasked with infiltrating the Saracen encampment. However, he was captured and forced to give up the name of the Assassin—Umar Ibn-La'Ahad—who had infiltrated Salāḥ ad-Dīn's personal tent and killed a nobleman during his escape that same night. Ahmad was nearly put to death until Umar stood up to take his place. After he was brought back into the fortress, Altaïr Ibn-La'Ahad blamed Ahmad for his father's death.
Prior to this, Ahmad contracted a fever in the Saracen camp, and later spent his time crying out Umar's name, while being treated to by Abbas. Some time after, in remorse over Umar's death, Ahmad entered Umar's home, spoke his apologies to Altaïr and then remorsefully committed suicide by slitting his throat with a dagger. In light of this event, Altaïr immediately ran to Al Mualim and told him what had occurred.
In response, Al Mualim bid Altaïr to keep quiet about what he had seen, and later told his fellow Assassins that Ahmad had ran away, to prevent Abbas from being judged for his father's shame. The truth surrounding the circumstances of Ahmad's death would eventually drive Abbas to develop an intense hatred for Altaïr once he knew, which culminated in the former's coup d'état of the Assassin Order in 1225.