General Motors officials expect an internal investigation to clear CEO Mary Barra of wrongdoing in the company's faulty ignition switch crisis, says The New York Times.

Former U.S. Attorney Anton Valukas has been digging into the matter for three months, interviewing GM insiders, including engineers and executives.

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At the heart of the investigation lies two questions: Who at General Motors knew about the faulty ignition switch, and when did they know it? And why didn't the automaker move faster to recall the switches in 1.3 million cars built between 2004 and 2008, says CNBC.

Valukas' findings are expected to call out each individual and department that played a role in ignoring the problem that led to 13 deaths. But GM officials seem confident that Barra will not be on the list.

Company officials, who spoke to the Times on condition of anonymity, have drawn optimism from findings by the National Highway Traffic Safety Administration. Last month David J. Friedman, the acting chief of that agency, was asked whether the 200,000 GM documents he reviewed indicated Barra knew about the defect.

“I don’t have any records of that,” Friedman said.

Since then, GM officials have ramped up support for Barra. One executive boldly stated that evidence linking Barra to the crisis doesn't exist, says the Times. And the previous GM chief executive, Daniel Akerson, reportedly said “I bet my life” Barra didn't know about the defect.

GM is looking to Barra to help the company regain credibility. But that is only possible if she is cleared of all wrongdoing.

If Valukas' report does show that Barra was unaware of the faulty ignition, it's not likely to placate the harshest critics, says the Times, especially since key questions have yet to be answered.

For instance, why was Barra, who headed product development from 2011 to 2013, in the dark when GM had internal studies citing the ignition problem? And why has Barra refused to discuss GM's settlement of a wrongful death lawsuit that was rapidly settled last year?

“There is so much riding on this report for Mary Barra,” Harvey Pitt, former head of the Securities and Exchange Commission, told the Times. “Lots of questions have been raised, and now she will have to answer them.”

Even if she is cleared of wrongdoing, analysts and investors will be looking for more. The investigation will get plenty of attention, writes CNBC's Phil LeBeau, but the changes GM puts in place following the probe will be of greater interest on Wall Street.

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