Washington (CNN) The House Oversight Committee launched an ethics investigation Monday into Transportation Secretary Elaine Chao, who has recently faced scrutiny for her ties to an international shipping company run by members of her family.

Chairman Elijah Cummings, a Maryland Democrat, wrote in a letter to Chao, Cummings said he was investigating multiple allegations against the secretary, "including troubling questions about whether you are using your office to benefit you and your family." The chairman also said he was probing Chao's "failure to divest of stock" in a construction company whose board she used to sit on.

The investigation comes several months after Chao came under fire her connections to the shipping company, the Foremost Group, which is based in the US but has ties to China. The company was founded by Chao's father and its current CEO is her sister. In June, CNN reported that Chao was receiving criticism from House Democrats and watchdogs who raised questions about whether Chao was using her position to benefit the company.

The investigation is the latest example of House Democrats using their oversight power to look into whether or not members of President Donald Trump's Cabinet are acting unethically in their official roles. The probe could be met with resistance by the administration, as other congressional investigations have been in recent months.

In a statement to CNN on Tuesday, a DOT spokesperson acknowledged that the department received Cummings' letter and that it was prepared to respond, adding, "Media attacks targeting the Secretary's family are stale and only attempt to undermine her long career of public service."

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