A car-safety advocate on Wednesday urged the lawyer overseeing General Motors Co’s program to compensate victims of accidents linked to a faulty ignition switch in its vehicles to take a more active approach to finding cases of injury or death. Clarence Ditlow, executive director of the Center for Auto Safety, said in a letter to Ken Feinberg, the lawyer overseeing the GM program, that Feinberg should expand outreach efforts and scour federal car-safety databases for accidents in recalled vehicles to determine whether the switch was to blame for additional injuries or deaths.