The inspector general's office is investigating Elaine L. Chao for allegedly using her office to financially benefit her family.
Chao, wife of Senate Minority Leader Mitch McConnell (R-KY), is accused of asking her office staff to make arrangements for her father's company, which has ties to China.
In 2019 the NY Times reported that Chao asked her staff to make business arrangements for herself, her father, James Chao, and sister, including a 2017 trip to China that was later canceled.
Her father, who owns a successful shipping business, was dubbed "Chinese Ship King," according to the Times.
Chao was transportation secretary under former President Donald Trump. The investigating was referred to the U.S. Justice Department, but they declined to look into the matter, according to the NY Times.
"A formal investigation into potential misuses of position was warranted," said Mitch Behm, deputy inspector general for the Transportation Department.
Chao resigned the day after the Capitol Hill riots on Jan. 7, but she claimed the investigation into her father's business dealings was not a factor in her decision to quit.