House Republicans ramped up pressure on the Department of Justice on Thursday to allow four witnesses to testify about the DOJ’s yearslong investigation into Hunter Biden, arguing that the department is prohibiting employees involved in the case from complying with congressional subpoenas.

The House Judiciary Committee indicated in a letter obtained by the Washington Examiner to Attorney General Merrick Garland that the DOJ had already instructed two Tax Division officials to defy their subpoenas.