The car crash that killed Gene Erickson caught the attention of federal regulators. Why did the Saturn Ion he was traveling in, along a rural Texas road, suddenly swerve into a tree? Why did the air bags fail? General Motors told federal authorities that it could not provide answers.

But only a month earlier, a GM engineer had concluded in an internal evaluation that the Ion had most likely lost power, disabling its air bags.

Now, GM’s response, as well as its replies to queries in other crashes obtained by The New York Times from the National Highway Traffic Safety Administration, casts doubt on how forthright the automaker was with regulators.

They provide details for the first time on the issue at the heart of a criminal investigation by the Justice Department: whether GM, in its interaction with safety regulators, obscured a defective ignition switch that GM has linked to at least 13 deaths in the last decade.

The company repeatedly found a way not to answer the question from regulators of what led to a crash. In at least three cases of fatal crashes, including the accident that killed Erickson, GM said that it had not assessed the cause. In another fatal crash, GM said that attorney-client privilege may have prevented it from answering.

And in other cases, the automaker was more blunt, writing, “GM opts not to respond.”

The responses came even though GM had for years been aware of sudden power loss in some models involved in the accidents.

The responses are found in documents known as death inquiries, which The Times obtained through the Freedom of Information Act. In those inquiries, regulators ask automakers to explain the circumstances surrounding a crash to help identify potential defects in cars.

Erickson was riding in the front seat of a Saturn Ion driven by Candice Anderson in 2004. They were an hour from Dallas when the car suddenly drove into a tree, killing Erickson but sparing Anderson. Only recently did Anderson, who pleaded guilty to criminally negligent homicide after the accident because she had a trace of Xanax in her system, learn that she was not to blame.

Despite the earlier determination by the engineer, Manuel Peace, that the engine’s shutting off had most likely been the reason for the crash, GM, in its response to regulators, said there may not have been “sufficient reliable information to accurately assess the cause” of the incident.

GM, which also faced a lawsuit from Erickson’s family at the time, further stated that attorney-client privilege may have been a reason it could not make any disclosures.

Ultimately, GM said it had not assessed the cause of the accident.

“It seems inconsistent,” said Carl Tobias, a law professor at the University of Richmond, who specializes in product liability. “It seems like the company knew that the accident was attributable to power loss. It does sound like they didn’t give NHTSA everything they should have. That could make them vulnerable to the Justice Department’s investigation.”

When asked about GM’s responses to the government’s death inquiries, James Cain, a spokesman, said Tuesday: “We are confronting our problems openly and directly. We are taking responsibility for what has happened and making significant changes across our company to make sure that it never happens again.”

In a later death inquiry, GM chose not to say whether it had looked into the circumstances of the December 2009 crash in Tennessee that killed Seyde Chansuthus, who is also counted among GM’s 13 victims.