I know nothing of the JFK assassination other than the very basics and general idea of the consiparicy, but I find this thread extremely interesting!

At any rate, I was reading up on James Files on wikipedia, and I wasn't too too skeptical about his story until I read this:

Files at one point was close to being featured in an NBC documentary, but the deal fell through when NBC decided to check out his story, and hired Edward Epstein to vet it.:
In brief, NBC retained me as a consultant for their planned story on Files. I hired the detective firm of Jules Kroll. JK established from telephone records Files was in Chicago, not Dallas, on November 22,1963. We then placed a call to Files from Dick Clark's office (DC was producer), and I interviewed Files about Kroll findings. He said he had a twin brother, who no one knew about, and whom he met shortly before November 22, and who he murdered after November 22. He said it was his twin brother in hospital with his wife, not him. His wife, however, said there was no twin, and Kroll confirmed there was no twin. My view then and now is that Files invented the story for the money it would earn him. However, James Files, in a letter he wrote to Mrs. Pamela Ray, a person with whom he developed a close relationship, said: "The Kroll Agency tried everything they could to discredit me. One story they put out was that I couldn't have been in Dallas that day, as my wife was giving birth to our daughter that day. When I was asked about it, I said yes, I was at the hospital that day. But that means Kennedy was not assassinated until September 26, 1966. I said that is the day my daughter was born, go check the hospital records. That ended that." Dutch JFK researcher Wim Dankbaar also counters the claims. Dankbaar also published a phone conversation with Faith Files, ex-wife of Files, who corroborated a number of claims, disputed by others.
Seems a little suspicious to me. "Oh yeah, that was my twin brother that I had just found out about, but I murdered him soon after I found out about him." Then to lie about the whole conversation he'd had in a letter to a friend. Kind of rules out any truth to his story.

But then again, I guess it could be NBC's people, and/or Kroll who are the liars, who knows.

The part that still seems interesting to me is that he says he shot the shot, bit the bullet casing, and left it at the grassy knoll. And evidently, they dug up a bullet casing at the grassy knoll, exactly as he described, with, what a dentist confirmed to be, teeth marks in it. This part is particularly interesting.