A crowd gathers around the car in which Salvadoran Attorney General Roberto Garcia Alvardo was assassinated in San Salvador Wednesday by unidentified assailants as he drove to his office. A bomb placed on the roof of Garcia's car exploded when the car stopped at a traffic light, according to the attorney general's driver. Salvadoran President-elect Alfredo Cristiani and U.S. Ambassador William Walker said Wednesday leftist guerrillas are trying to provoke human rights abuses by the armed forces and new government.