For decades, I've believed President John F. Kennedy was the victim of a conspiracy of assassins, not a single, tormented soul with a bolt-action rifle.

I read my first conspiracy book as a teenager - Inquest by Edward Jay Epstein. Others followed, including David Lifton's Best Evidence, which can convince you in 747 engrossing pages that conspirators snatched Kennedy's body from his coffin on the day of the assassination and altered his wounds to pin the crime on Lee Harvey Oswald, in effect creating a forensic forgery.

 

It's all fascinating, and I could listen to this stuff all day.

But now, 50 years after the assassination I'm coming to terms with the likelihood that it wasn't a conspiracy, and that the Warren Commission got it right - that Oswald acted alone, that there was no second gunman, and that the long-ridiculed "single bullet" theory which found Kennedy and Texas Gov. John Connally were hit by the same round, is accurate.

How do you know?

As the 50th anniversary of the assassination approached in recent weeks, I and the Fresh Air staff considered what kind of interview would best mark the occasion.

What I wanted was a smart, fair-minded scholar or journalist who's looked at all the evidence - the Warren Commission report, the findings of the House Select Committee on Assassinations, and all those damn books - and could tell us if there's a consensus among serious, credible analysts about some of the long-asked questions about the assassination.

I think we found the right guy in Philip Shenon, a veteran investigative journalist who worked for many years at the New York Times and wrote a respected book about the 911 Commission.

For his new book, A Cruel and Shocking Act, Shenon took a hard look at the Warren Commission investigation, interviewing many of its surviving staff attorneys and investigators, poring over records, and doing original research on some aspects of the case.

What he found was that a talented and dedicated crew (including the late Arlen Specter) did their best to get to the truth despite interference from the commission chairman and unconscionable obstruction from the FBI and the CIA.

As Shenon explains on our Fresh Air interview today,  the FBI and CIA lied to the commission, withheld information and destroyed evidence in the case. Some of the resulting shortcomings of the Commission's work fed conspiracy theories which spawned quickly and kept coming for 50 years (a new book by Republican consultant Roger Stone says Lyndon Johnson was behind it).

The irony is that the Warren Commission may have answered all the big questions correctly, but lacked credibility because so many powerful interests tried to control and manipulate its investigation.

If you find the JFK case as interesting as I do, or if you're too young to know much about it but want to learn more, listen to today's Fresh Air.

It airs at 3 and 7 p.m. on WHYY. If you're outside the Philadelphia area, find a station here.