The lucrative government contract, to provide security for federal courthouses and cell blocks, went to CertiPath, a Reston, Va.-based company that has since 2013 been owned in part by a firm linked to Robert S. Trump, the president’s younger brother.

After the contract was awarded, an anonymous rival bidder filed a complaint with the Justice Department’s office of the inspector general, alleging that CertiPath failed to disclose that “one of the President’s closest living relatives stood to benefit financially from the transaction,” according to a copy of the July 22 complaint letter obtained by The Washington Post.

“The circumstances of this contract award, and what appear to be CertiPath’s efforts to obscure Mr. Robert Trump’s financial interest in the company even as it trades on the Trump name, present the appearance of preferential treatment for those who are close to the President,” said the complaint, which was sent by Venable, a Washington law firm, on behalf of the client.