United States Department of Transportation
The potential ethics violations were sent last year to the Justice Department, which declined to investigate Trump's transportation secretary.
Three leading congressional Democrats have demanded that Mitch Behm be reinstated as the Transportation Department’s acting inspector general.
Chao has been accused of using her office to benefit herself and her family's shipping company.
The announcement comes one day after California joined a 16-state lawsuit challenging the president's emergency declaration to fund a border wall.
WHAT'S HAPPENING
Stealing copper wires from light poles creates dangers and forces costly repairs.
Department of Transportation data show that 18 pets died last year in United's cargo program.