(Reuters) - U.S. federal prosecutors have learned that lawyers for General Motors Co were present at key meetings during which information about problems with some of its vehicles were discussed, a source close to the investigation said.

The prosecutors from the U.S. Department of Justice have asked how lawyers attending those meetings participated in them and what they did afterward with the information that was shared during the meetings, the source said.

General Motors had issued a report in June which detailed how for 11 years it turned a blind eye to an ignition-switch problem linked to at least 13 deaths but largely pinned the blame on what the report described as incompetent lower-level employees, leaving top brass untouched.

Lower-level lawyers are among the 15 people GM has dismissed in the safety debacle that has resulted in millions of recalled vehicles.

"We're cooperating fully," a representative from the company said.

The Justice Department was not immediately available for comment outside of regular U.S. business hours.

Employees within the No.1 U.S. automaker's legal department are being scrutinized for concealing evidence from regulators about a faulty ignition switch, the Wall Street Journal reported, citing sources. (on.wsj.com/VJn4Vt)

Concealing evidence about the faulty ignition switch could have led to a potential delay in the recall of the affected vehicles, the Journal said.

U.S. senators in July demanded to know why General Motors did not fire its top lawyer, General Counsel Michael Millikin, after it was revealed this year that the automaker's litigation department knew of a widespread and deadly ignition flaw but failed to escalate the safety issue.