Now, CBS News has found another death that may be linked.
"When I saw my daughter in the emergency room and I kissed her cold forehead, I said, I will vindicate this. I will vindicate your death. And I will try to save as many lives as I can," said her father, Ken Melton.
Five years before Brooke Melton died, General Motors issued a service bulletin to its dealers about faulty ignition switches.
When Brooke Melton took her car to a GM dealership, the service report, which CBS News obtained, said "Customer states engine shut off while driving, please check."
Technicians cleaned the fuel injection.
Melton got the car back on March 9. She was killed March 10.
GM settled with the family last year.
Complete Coverage: General Motors Recall
Lance Cooper, who represents the Meltons, says he believes the recall would not have happened if the family had not sued.
GM now says ignition switches can turn to off or accessory when they're bumped, or if a driver has a heavy key ring. When that happens, a car has no power steering, no power brakes, and the seat belts and airbags don't work.
Cooper discovered that GM changed the switch design in 2006 but never notified customers or dealers. When the settlement offer came, he was about to depose Jim Federico, the man who ran GM's investigation into the issue in 2012 and 2013. Federico is now the company's executive director of engineering.
Did Cooper every receive all the information he wanted from GM?
"No," the lawyer said. "It was clear to us they had not produced a number of documents in violation of the court order."
Does Cooper think GM ever would have given him all those documents?
"No." Cooper said. "I think that ultimately that's why the case resolved because they did not want us to have all those documents."
CBS News asked to speak with Federico or anyone involved in the investigation at GM. The company declined.
Right now, Brooke Melton's case is not among the crashes GM says are linked to the defect. GM has acknowledged front-impact crashes, when airbags haven't deployed. But after her car lost power, Melton was hit on the side.
If GM were to acknowledge that Melton's death was linked to the ignition issue, how much more complicated would that make this case for the automaker?
"Much more complicated," said Cooper, "because it's no longer a non-deploy of the airbag investigation, it's an overall 'What happens when the ignition switch causes the key to turn off?' investigation."
GM has hired an outside law firm to help its internal investigation. That's being done by the former U.S. attorney whose examined the collapse of Lehman Brothers.
GM says it wo n't have the parts to begin the repairs until April.
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