"Hey now, wait. Standby on these," the pilot cautioned. "They could be animals in the field." Seconds later, tiny white flashes appeared by the figures — the heat signature of gunfire. "There they are," he said, now sure he was looking at the enemy.
Thirty-one seconds after the pilot reported muzzle flashes, the Marines at Alcatraz ordered that the Predator be prepared to strike if the shooters could be confirmed as hostile. At 8:49 a.m., 29 minutes after the ambush began, they authorized the pilot to fire. In minutes, two Americans would be dead.