Tonight, we have details of a classified US intelligence mission that has obtained a previously unknown weapon that may finally unlock a mystery. Since at least 2016, US diplomats, spies, and military officers have suffered crippling brain injuries. They've told of being hit by an overwhelming force damaging their vision, hearing, sense of balance, and cognition. But the government has doubted their stories. They've been called delusional. Well, now 60 Minutes has learned that a weapon that can inflict thes ...