THE THIRD BULLET. By Stephen Hunter. Simon & Schuster. 485 pages. $26.99.

This Nov. 22 will mark the 50th anniversary of the assassination of President John F. Kennedy. One of America’s darkest days will be remembered, and still persistent conspiracy theories will be resurrected.

But in case you have not heard, there is finally closure on that conspiracy question. The answer is, yes, there was a second gunman and a third shot. At least that’s what Stephen Hunter says really happened, according to his latest Bob Lee Swagger novel, “The Third Bullet.”

Swagger is Hunter’s heroic and laconic ex-Marine sniper who becomes quite the snooper after being asked to investigate a journalist’s murder, which leads him to probe one of America’s ultimate slayings.

Hunter, a former Washington Post film critic, is the author of 18 novels. In “The Third Bullet,” Hunter crafts a complex conspiracy involving, at various levels, the usual suspects: the CIA and the Soviets.

Lee Harvey Oswald is the triggerman, but is not the only (or most accurate) triggerman.

If there really was more to Kennedy’s assassination than the twisted motivations of Oswald, Hunter’s scenario comes across as plausible. The author gives plenty of first-person voice to the real assassination architect, a brilliant covert operations mastermind who manipulates the loser, glory-hungry Oswald, who recruits a talented sniper associate.

The story plays to Hunter’s strength in all things guns. The weaponry is the key to pulling off the crime and getting away with it, until years later when Swagger starts to see through the culprit’s vanishing act.

“The Third Bullet” is an intriguing tale of American patriots who really aren’t, and of dead people who really aren’t.

If you think Bob Lee Swagger is JFK’s avenging angel, think again. Ever the anti-hero, Swagger isn’t out to bring justice to the Kennedy killers. No, he’s after the villains behind Oswald’s sidewalk slaying of the Dallas police officer shortly after the president was shot. That’s what really angers Swagger about Nov. 22, 1963.

If you still believe Oswald was not capable of committing this heinous crime by himself, then “The Third Bullet” will satisfy your skepticism. Or if you just appreciate great characters, details, storytelling and suspense, this book fills the bill also.

Reviewer Patrick Harwood is professor of communication at the College of Charleston.