Spencer

Spencer is not your average girl. Spencer is 16 and has no family. Her family died in a car accident and she was the only one who lived through it. She currently works with the C.I.A., and lives with her dad's best friend. But there is a mystery, when her family died a truck hit them. But there was no one in the truck, and the car accident was on the highway. That truck got on the highway but it wasn't an accident.
So the question is who killed her family and why?