Hien Tran lay dying in intensive care this month after a car accident, as detectives searched for clues about the apparent stab wounds in her neck.
An unlikely breakthrough arrived in the mail a week after she died from her injuries. It was a letter from Honda urging her to get her red Accord fixed, because of faulty air bags that could explode.
“The air bag,” said Tina Tran, the victim’s twin sister. “They said it was the air bag.”
Ms. Tran became at least the third death associated with the mushrooming recalls of vehicles containing defective air bags made by Takata, a Japanese auto supplier. More than 14 million vehicles from 11 automakers that contain the air bags have been recalled worldwide.