The chairman of the House Committee on Oversight and Reform on Monday said the committee was launching an investigation into whether Secretary of Transportation Elaine Chao used her office to help the shipping company owned by her father and sisters.

In a letter to Chao, Rep. Elijah E. Cummings, D-Maryland, requested information and documents about media reports that Chao had appeared alongside her father in at least a dozen Chinese media interviews, sometimes behind the official seal of the Department of Transportation, in order to benefit Foremost Group, the family shipping company.

“During some of these interviews, your father touted your influence within the United States government and boasted about his access to President Trump on Air Force One,” read the letter, also signed by Rep. Raja Krishnamoorthi, D-Illinois, chairman of the Oversight panel’s Subcommittee on Economic and Consumer Policy.

Chao is married to Senate Majority Leader Mitch McConnell.

The committee also questioned whether Chao’s involvement in decisions, including a reduction of funding for Department of Transportation programs helping U.S.-flagged vessels in foreign trade, might have helped her family’s company, which owns only foreign-flagged ships.

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And it requested information on why she failed to divest her stock in Vulcan Materials Co., a Birmingham, Alabama-based construction company. Chao served on the board of directors of that company for two years before becoming Secretary of Transportation and Vulcan’s annual revenue depends heavily on infrastructure funding allocated by the Department of Transportation, Cummings and Krishnamoorthi wrote.

They said while Chao promised prior to her confirmation hearing to cash out her stock holdings in Vulcan by April 2018, she did not sell her shares in the company until June 3, 2019, after the Wall Street Journal published an article about her failure to divest.

The letter requested all communications between Department of Transportation officials and Angela Chao, Elaine Chao’s sister, and the chairman and CEO of Foremost, or James Chao, her father and the founder of the company, as well as other representatives of Foremost Group. It also requested items including unredacted copies of all information sent to the New York Times in response to a 2017 Freedom of Information Act request and a list of all media interviews conducted with both Chao and members of her family since Jan. 20, 2019.

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A Transportation spokesperson confirmed that the department had received the letter and will “look forward to responding to the Committee’s request.”

“Media attacks targeting the Secretary’s family are stale and only attempt to undermine her long career of public service,” the spokesman said.

The committee has asked Chao to respond to the letter and provide the requested documents by Sept. 30.