House Intelligence Committee chairman Devin Nunes has issued a subpoena to David Kramer, a former State Department official who, in late November 2016, traveled to London to receive a briefing and a copy of the Trump dossier from its author, former British spy Christopher Steele. Kramer then returned to the U.S. to give the document to Sen. John McCain.

Kramer is a senior fellow at the McCain Institute for International Leadership at Arizona State University.

McCain later took a copy of the dossier to the FBI’s then-director, James Comey. But the FBI already had the document; Steele himself gave the dossier to the bureau in installments, reportedly beginning in early July 2016.