Retired Lieutenant Colonel Bill Burkett, who has been pressing his charges in the national news media this week, says he even heard one high-ranking officer issue a 1997 order to sanitize the Bush file, and later saw another officer poring over the records and discovered that some had been discarded.

But a key witness to some of the events described by Burkett has told the Globe that the central elements of his story are false.

George O. Conn, a former chief warrant officer with the Guard and a friend of Burkett's, is the person whom Burkett says led him to the room where the Bush records were being vetted. But Conn says he never saw anyone combing through the Bush file or discarding records.

"I have no recall of that," Conn said. "I have no recall of that whatsoever. None. Zip. Nada."

Conn's recollection also undercuts another of Burkett's central allegations: that he overheard Bush's onetime chief of staff, Joe M. Allbaugh, telling a Texas Guard general to make sure there were no embarrassments in the Bush record.

Burkett says he told Conn, over dinner that same night, what he had overheard. But Conn says that, although Burkett told him he worried that the Bush record would be sanitized, he never mentioned overhearing the conversation between Allbaugh and General Daniel James III.