In a brief telephone interview on Tuesday, Dr. Hatfill said that was not true. He said he was ousted as part of “a coup to overthrow Mr. Kennedy” that he claimed was being organized by Matt Buckham, Mr. Kennedy’s chief of staff. But he did not explain why his ouster was evidence of the effort. Dr. Hatfill said that Mr. Buckham had told him that the secretary wanted “to go in a different direction” and had asked him to resign.