KABUL, Afghanistan (AP) - A bomb blast south of the Afghan capital killed three people and wounded another on Saturday, police said. The remote-controlled device went off as a car carrying four people passed by on the main road in Musayi district, Kabul province, said Ali Shah Paktiawal, a police official.The victims were all Afghans working for a local private security firms that provide services to local and international non-governmental organizations, said Mohammad Daud Nadim, regional police chief.