Ahmed Wali Karzai, the brother of the Afghan president and a suspected player in the country's booming illegal opium trade, gets regular payments from the Central Intelligence Agency, and has for much of the past eight years, according to current and former American officials. The C.I.A.'s practices ... suggest that the United States is not doing everything in its power to stamp out the lucrative Afghan drug trade, a major source of revenue for the Taliban. The relationship between Mr. Karzai and the C.I.A. is wide ranging. He helps the C.I.A. operate a paramilitary group, the Kandahar Strike Force, that is used for raids against suspected insurgents. On at least one occasion, the strike force has been accused of mounting an unauthorized operation against an official of the Afghan government. Mr. Karzai is also paid for allowing the C.I.A. and American Special Operations troops to rent a large compound outside the city. He's our landlord," a senior American official said, speaking on the condition of anonymity. A former C.I.A. officer with experience in Afghanistan said the agency relied heavily on Ahmed Wali Karzai, and often based covert operatives at compounds he owned.