Two top Republican senators requested Hunter Biden’s official travel records Wednesday from the Secret Service in the latest move of their ongoing investigation into Biden’s conflicts of interest.

Sen. Chuck Grassley of Iowa, who chairs the Senate Finance Committee, and Sen. Ron Johnson of Wisconsin, who leads the Senate Committee on Homeland Security and Government Affairs, penned a letter to the Secret Service to learn whether Biden “used government-sponsored travel to help conduct private business” stemming from his work with overseas nations.

The committees, the senators wrote, is “reviewing potential conflicts of interest posed by the business activities of Hunter Biden and his associates during the Obama administration, particularly with respect to his business activities in Ukraine and China.”

In 2013, Biden flew aboard Air-Force Two with his father Vice President Joe Biden to China and arranged meetings with Chinese businessmen. Soon after, a series of transactions followed that benefited Hunter Biden’s firm, BHR. Hunter Biden also served on the board of the Ukrainian natural gas company Burisma, raking in upwards of $50,000 a month despite no prior experience in the industry while his father dictated U.S. policy towards Ukraine as vice president.

A Federalist analysis of Hunter Biden’s pay reveals just how much Biden was being showered in excess compensation. According to Reuters, Burisma reported $400 million in revenues in 2018, while Exxon Mobil reported earnings of $20.8 billion. Board members for Exxon Mobil, however, earned little more than half what Biden was bringing in from Burisma.

Grassley and Johnson have requested the Secret Service to:

1. Please describe the protective detail that Hunter Biden received while his father was Vice President. 2. Please provide a list of all dates and locations of travel, international and domestic, for Hunter Biden while he received a protective detail. In your response, please note whether his travel was on Air Force One or Two, or other government aircraft, as applicable and whether additional family members were present for each trip.

The letter comes on the same day President Donald Trump was acquitted on both impeachment counts passed by the House in December charging Trump with “abuse of power” and “obstruction of Congress.”

House Democrats accused Trump of pressuring Ukrainian President Volodymyr Zelensky to investigate corruption related to the Biden family in exchange for nearly $400 million in withheld military aid in an alleged quid pro quo. The aid, however, was ultimately released to the eastern European nation by the congressionally mandated deadline without a single investigation in Ukraine that the president allegedly demanded.

The Senate voted to acquit Trump on the “abuse of power” charge 52-48 and “obstruction of Congress,” 53-47. Utah Sen. Mitt Romney was the only Republican to cross party lines and vote to convict Trump on abuse of power. Democrats needed 67 votes, a two-thirds majority, to remove Trump from office.