Today, investigative journalist Edward Jay Epstein disputed a dramatic anecdote from Bill O'Reilly's 2012 book Killing Kennedy, writing a point-by-point refutation of the Fox News host's story titled "O'Reilly's JFK Reporting Was Impossible. I Know Because I Was There."

In the book, O'Reilly claimed to have been standing outside the Florida home where Lee Harvey Oswald associate George de Mohrenschildt killed himself, hearing the gunshot firsthand, an account questioned by the website in 2013 and further interrogated by Media Matters last month.

Epstein, however, has unique expertise on the topic as the author of Legend: The Secret World of Lee Harvey Oswald and, by his own account, "the actual—and only—reporter interviewing de Mohrenschildt on the last day of his life in 1977."

Accusing O'Reilly of "reality deficiency disorder," Epstein offered a number of key details that differ from the Killing Kennedy story, including the location of the suicide and the audibility of the gunshot.

Additionally, Epstein pointed to audio tapes that purportedly show O'Reilly was in Dallas on the date of de Mohrenschildt's death, including a phone call where investigator Gaeton Fonzi seems to inform O'Reilly of the suicide.

In the essay, Epstein offers an imaginative theory as to how the Fox News host could have been in both Florida and Texas at once:

In his 2012 account, the inventive O'Reilly may have been emulating the time-traveling investigator Jake Epping, who went back in time to solve the JFK assassination in Stephen King's 2011 best-selling book 11/22/63. Epping in that book used time travel to drop in on George de Mohrenschildt before he killed himself. But of course Epping's feat was pure fiction.

On his show Monday, O'Reilly briefly addressed Epstein's claims, dismissing it as another "far-left attack" on his reporting and pointing to a statement from former colleague Bob Sirkin that—while not directly addressing the gunshot story—states, "It remains preposterous for anyone to claim that O'Reilly and I were not in Florida before, during, and following de Mohrenschildt's death."

[Image via AP Images//h/t Mediaite]