General Motors internal probe of its delay in recalling vehicles with defective ignition switches linked to at least 13 deaths said senior managers were not to blame, a person familiar with the matter told Reuters on Thursday.

The automaker’s report also concludes that there was no concerted cover-up of the faulty parts, instead pointing to cultural failings at the company, according to the source, who is familiar with the contents of the report.

The findings, were first reported by the Wall Street Journal, are expected to be made public later.

GM spokesman Jim Cain declined to comment about the report ahead of its release by the company.

The source confirmed that the report concluded Chief Executive Officer Mary Barra, executives who reported directly to her, the board of directors and former CEO Dan Akerson did not know about the defective switches before December.

It also found that GM’s general counsel, Michael Millikin, was not responsible for the mishandling of defects and the recall delay, the source said. Millikin, who led the internal probe with former U.S. prosecutor Anton Valukas, is expected to continue working at GM.

GM on Thursday is also expected to announce that some employees will be dismissed, according to the source, who could not be named because the report is not yet public.

The report is also likely to call for the creation of a new operational risk-management committee to closely monitor how top executives handle potential risks, the source confirmed.