..what the government did not say was that Mr. Juma Khan was also a longtime American informer, who provided information about the Taliban, Afghan corruption and other drug traffickers. Central Intelligence Agency officers and Drug Enforcement Administration agents relied on him as a valued source for years, even as he was building one of Afghanistan’s biggest drug operations after the United States-led invasion of the country, according to current and former American officials. Along the way, he was also paid a large amount of cash by the United States.