An investigation by the Pentagon’s inspector general has cleared acting Defense Secretary Patrick Shanahan of allegations that he attempted to exert undue influence on behalf of his former employer, Boeing.

The ethics probe began after a watchdog group, Citizens for Responsibility and Ethics in Washington, sent a letter to the inspector general pointing to media reports that Shanahan was “boosting” Boeing in Pentagon meetings. The group questioned whether Shanahan harbored an unfair bias against other big military contractors.