Listen to an excerpt from The Cold Six Thousand, available as an Audio Book from Random House.

“America was never innocent” are the first words of American Tabloid, James Ellroy’s best-selling 1995 novel about the John F. Kennedy assassination, in which he took various elements of conspiracy-theory lore, added his own fictional designs, and wove them all into a long, twisted narrative involving mobsters, Cuban exiles, rogue CIA agents, and freelance G-men. The opus ended seconds before the shots were fired, and Ellroy’s new novel, The Cold Six Thousand (Alfred A. Knopf), picks up moments afterward, continuing until 1968 and connecting other catastrophes of the era—the assassinations of Robert Kennedy, Jr., and Martin Luther King, Jr., as well as the Vietnam War—to the same dark forces that brought about JFK’s murder. Ellroy’s fiction has always plumbed the depths of terrible knowledge, both personal and political. He delights in wrecking sentimental notions of innocence; hence his obsession with the assassination, an event considered by many to be the dying gasp of America’s golden youth before the onset of modern maturity—and depravity. Nonsense, Ellroy told me. We’ve always been corrupt, and the Kennedy assassination is just the most conspicuous proof. Michael Hall.

I was fifteen when Jack the K ate lead in Dealey Plaza. I vividly recall his ascent—all of a sudden the world was about this guy with a funny accent. And his death meant absolutely nothing to me. I was my dad’s son. He was a Nixon guy, he was a Republican, ergo I was too. So I lived through the actual event and the preposterous Jim Garrison crap of 1967 to 1969 and Mort Sahl’s reviving the case on TV in the late sixties and never gave a rat’s ass about it until 1988, when I read Don DeLillo’s Libra. The genesis of American Tabloid and The Cold Six Thousand was my reading of Libra. It is a brilliant fictional speculation on who killed Jack the K, and it also posits implicitly the heretical notion that Jack got what he deserved by the rules he lived by. And I firmly believe that. I found Libra‘s theory of the assassination—that it was perpetrated by an unholy amalgam of whacked-out Cuban exiles pissed off at the Bay of Pigs betrayal, renegade CIA men (not the CIA as an entity, but CIA contract men), and the mob—wholly plausible. Regardless of what happened in real life, the most compelling theory, the most plausible, was that nexus. It came back to the dual agendas of money and turf, meaning Cuba, which makes Jack’s death the world’s most auspicious business-dispute homicide.

And it’s a tremendous story of geopolitical hubris and naiveté. Jack took aid from the mob in the primary election in 1960 in West Virginia and let the Chicago machine stuff ballot boxes for him in Illinois. He appointed his rabid pit-bull brother Bobby attorney general, and Bobby went after gangsters who were siding with Cuban exiles, especially Carlos Marcello. He betrayed the Cuban exiles at the Bay of Pigs, and when he visited the Orange Bowl to talk to the ransomed Bay of Pig survivors at Christmas 1962, he promised them that the brigade flag would fly in a free Havana. And he thought they wouldn’t kill him! I realized when I read Libra that I could never write a book about the assassination. DeLillo had staked his claim. Then I said, “Wait, wait, wait, you don’t need to. You can write a book about 1958-1963 America. You can write a much larger book, and the Jack hit can be an off-page climax to volume one.” So American Tabloid begins November 22, 1958, and ends five years to the day later. We see that Bobby Kennedy is staking his claim as crime fighter number one, as chief counsel for the McClellan rackets committee. We see that Mr. Hoover hates Bobby because Bobby’s a real crime fighter and Mr. Hoover’s an old poof who’s hassling these dipshit Commies and leftists. We see that Castro’s getting ready to take over Cuba. We see that the mob very shortly will lose their casinos and a couple hundred grand a day in 1959 money. They’re mad.

You know, if I could go back and actually witness some of this, I’d love to go have a cup of coffee at Jack Ruby’s Carousel Club and assess Ruby’s mental state. DeLillo and I had breakfast once at a book fair in Amsterdam, and I said to him, “Jesus, wouldn’t you love to go back to October of ’63 and hang out at the Carousel Club?” And I’d love to be a fly on the wall during Oswald’s interrogation. I’d love to listen in on all those frenzied phone calls from J. Edgar Hoover to Henry Wade. I’d love to watch the consensus start to settle in, this conclusion that was reached, that this is the best for business. I’d like to see just how unconscious it was. And how pervasive it was and how nobody had to voice it.

Because ultimately the assassination was not a hugely orchestrated thing—it was carried out ad hoc, and more than anything else, it was an exercise in consensus thinking. At some point Carlos Marcello said, “Let’s do it,” and I think from then on it got very diffuse. People were operated through cutouts, and they didn’t know who the other people involved in this thing were. There’s a riff DeLillo does toward the end of Libra where he talks about “ambivalence and fixed will and what the weather was like”—these were the reasons for the success of the assassination. What cracks me up is that people think that the cover-up had to be orchestrated at the top levels of government.

The one question I will never answer about American Tabloid or The Cold Thousand is what’s real—what’s literally real and what’s not. Although JFK really did have a Dr. Feelgood, the New York doctor Max Jacobson. It’s a very, very strong theory that Jack was flying on liquid methamphetamine during the Cuban Missile Crisis. What Max Jacobson dispensed to Tennessee Williams, Cecil B. DeMille, and Truman Capote or really anybody with the money in the fifties and sixties was called joy juice. It was pure, pure pharmaceutical liquid methamphetamine cut with hormones and massive doses of B complex vitamins. And he was giving Jack shots of that, and Bobby didn’t like it and had Jack pee into a cup or something and had it analyzed. And Jack said, “I don’t care if it’s horse piss. It’s the only thing that works.”

Ultimately, though, if we were to find out tomorrow who killed JFK, nothing would change. It’s just a riddle for people to plumb. It gives a lot of the sad-sack researchers something to do that they think is important. If we were to know conclusively tomorrow exactly who called the shots and exactly who pulled the trigger and get detailed and forensically verified confessions from them, well, guess what, we’d still have war and pestilence and a fluctuating economy and all kinds of interesting and bad stuff happening in America and it would wash off the front page in a couple of weeks and there might be a movie. And it might do well and somebody might get a good book deal out of it and that’s that. And then—you know what?—some people would come along and challenge it. It’s irrelevant. We’re never going to know exactly what happened.

How much of my conclusion do I actually believe? I’ll say this: It’s the most plausible scenario, and it has remained the most plausible scenario for many years. And if it didn’t happen this way, it sure is a hell of a story.