Patrick Shanahan has been Acting Defense Secretary since January (Picture: US Department of Defense).
Investigators at the Pentagon have launched an inquiry into the Acting US Defense Secretary, Patrick Shanahan, for alleged favouritism towards his former employer, Boeing.
Mr Shanahan is accused of frequently praising Boeing in meetings about government contracts and acquisitions.
He denies any wrongdoing.
Mr Shanahan, who formerly worked at Boeing for 30 years, rose through the ranks to become the company's senior executive.
Last week Citizens for Responsibility and Ethics in Washington filed a complaint with the Pentagon inspector general about Mr Shanahan.
A spokeswoman for the inspector general, Dwrena Allen, said in a statement seen by several media outlets:
"The Department of Defense Office of Inspector General has decided to investigate complaints we recently received that Acting Secretary Patrick Shanahan allegedly took actions to promote his former employer, Boeing, and disparage its competitors."
Mr Shanahan said last week, during a Senate Armed Services Committee hearing, that he would support an investigation by the inspector general.
He has been Acting US Defense Secretary since January.