criminal investigation concerning the handling of a faulty ignition switch that would suddenly turn the car's power off, cutting off airbags, power steering, and power brakes. more than 2 million gm cars with the problem have been recalled. but as cnn's drew griffin reports, they will not say which vehicles are involved in the deadly defects, not even the families of the victims. >> reporter: gordon's son was just shy of his 21st birthday heading home on this road four years ago when in an unexplained flash, his 2007 pontiac g-5 locked into a turn, hit this very tree and ben died. >> even if i had been there i don't think how quickly i would have been hitting the tree. >> he stayed overnight with friends before driving home about noon on a sunday.