General Motors launches an internal investigation into how the company handled a recall linked to more than a dozen deaths.
GM recalled roughly 1.4 million cars last month because of a problem with the ignition switch that could cause cars to easily be shut off while driving.
The faulty switch is linked to 31 frontal crashes and at least 13 deaths over several years.
Documents submitted to federal safety regulators reveal some GM engineers knew of the problem 10 years ago but did not immediately treat it as a safety concern.
The National Highway Traffic Safety Administration is investigating whether GM responded quickly enough in recalling the car.
Automakers are required to inform federal regulators of safety defects within five days of discovering them.