Security forces have arrested a Tajik suspected of organizing the deadly car-bombing of a U.S. security firm in the Afghan capital and believe he was acting on the orders of al-Qaida, an Afghan official said Saturday. The suspect, Mohammed Haidar, confessed to his leading role in the Aug. 29 car-bomb attack, which killed about 10 people, including three Americans. A spokesman for the Afghan intelligence service, Mohammed Nader, said the report was accurate but declined to discuss the details. Haidar also admitted organizing an Oct. 23 suicide attack on a Kabul shopping street that killed an American woman and an Afghan child, the TV report said. The attack was allegedly carried out by a Kashmiri militant.