(CNN) An employee for the federal agency supervising the lease for the Trump hotel in Washington spent more than $900 for a stay there last year, according to a document reviewed by CNN -- the first publicly known movement of federal taxpayer dollars into the highly scrutinized business.

The federal employee worked for the General Services Administration, the agency which supervises the lease of the Old Post Office building to the Trump Organization.

The GSA reimbursed the employee for a majority of the charges, which was in line with the agency's policy on per diem expenses, according to a person familiar with the document. That means taxpayer dollars made their way into the hotel's coffers.

The expenses are small relative to the hotel's operation but the charge demonstrate how taxpayer money can flow into the President's businesses, stoking critics who say these payments invite corruption. Ethics hawks argue that Trump shouldn't profit from government money -- foreign or domestic and regardless of the amount.

CNN reviewed government travel expense records from the GSA, which were obtained via a Freedom of Information Act request by a government transparency group called Property of the People, a Washington-based nonprofit.

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