There are a lot of implausible theories about who killed President Kennedy. The notion that one man alone killed the president for no reason is one of them. So the possibility of conspiracy has to be taken seriously.

Unfortunately, on the 50th anniversary of JFK's death, most major news organizations still seek to portray a belief that Kennedy was killed by his enemies as the irrational conclusion of emotionally needy people seeking to ward off the painful "truth" that one deranged person could change history.

"If you put the murder of the president of the United States at one end of the scale, and you put that waif [Lee Harvey] Oswald on the other end, it just doesn't balance,'' said the much-quoted author William Manchester. "And you want to put something on Oswald's side to make it balance. A conspiracy would do that beautifully. Unfortunately, there is no evidence whatever of that."

Yet plenty of astute people have disagreed, most recently Secretary of State John Kerry, who recently expressed "serious doubts" about the Warren Commission's lone gunman conclusions. President Lyndon Johnson, JFK's successor, publicly endorsed the lone gunman theory but privately disparaged it. Likewise JFK's widow, Jackie, and brother, Bobby. Even Sen. Richard Russell, a member of the Warren Commission, privately rejected the commission's findings. H.R. Haldeman, chief of staff for President Nixon, wanted to reopen the JFK investigation in 1969. (Nixon wasn't interested.)

So where does the truth lie? As a journalist, I prefer to write about facts, not theories. In my view, none of the available theories shows beyond a reasonable doubt that any one individual plotted to kill JFK.

But as a working reporter who has written about the JFK story for 25 years, I am struck by two revelations emerging from the mass of 4 million pages of assassination-related records declassified since Oliver Stone's movie, both of which lend credence the idea that certain CIA officers may have connived in JFK's death.

The first is that Lee Harvey Oswald was watched far more closely by top CIA officials than the American people were ever told. Major news organizations still don't report the new evidence, but it is now a documented fact that undercover officers reporting to CIA counterintelligence chief James Angleton tracked Oswald's every move from when he defected to the Soviet Union in October 1959 until he returned from Mexico City in October 1963. Angleton's people watched Oswald all the way to Dallas.

The CIA told investigators in the 1960s and 1970s that it had only a "routine" interest in Oswald before JFK was killed and no reason to think he was a security threat. That claim has been exposed as a lie.

The new records show that Oswald was the subject of extraordinary interest all along. In 1961, he was part of a group of only 300 Americans whose mail was intercepted, opened and read. When the FBI interviewed Oswald in August 1962, the report was sent straight to Angleton's staff, as was an FBI report on Oswald's arrest for fighting with members of a CIA-funded anti-Castro group in August 1963. When Oswald traveled to Mexico City in October 1963, his visit was reported to senior officers reporting to Angleton and to deputy director Richard Helms.

The second aspect of the JFK story that arouses conspiratorial suspicion is the revelation, first published on my Web site, JFK Facts, that thousands of pages of assassination-related records have never been made public by the CIA. There is reason to believe that these records might shed light on the events, because they include information on CIA personnel who figure in the assassination story.

According to the National Archives online database, these classified records concern the secret operations of CIA officers David Phillips and Anne Goodpasture, both stationed in Mexico City, who knew about Oswald's leftist politics and foreign contacts in late 1963 yet raised no security concerns about him.

Phillips' later gave misleading and contradictory testimony to Congress, prompting several investigators to allege he was involved in a conspiracy to kill JFK. Phillips rejected the charge, but told an acquaintance he thought JFK had been killed by rogue CIA officers.

More than 100 pages from the files have to do with Bill K. Harvey, a legendarily brash operative who organized several unsuccessful CIA conspiracies to kill Fidel Castro. His undisguised contempt for President Kennedy and his brother Bobby cost him a high-level job in mid-1963.

Other secret files concern E. Howard Hunt, the CIA officer who later gained notoriety as a Watergate burglar, and David Morales, chief of anti-Castro paramilitary operations in Miami. Both men are known to have made statements late in life suggesting they knew about a plot to kill JFK

Did one or more officers (all of whom are deceased) conspire to kill Kennedy? There's no proof of that, but it's not an unreasonable or paranoid question. Without all the evidence, it would be premature to dismiss the possibility. Only full disclosure by the CIA can dispel conspiratorial speculation. Unfortunately, the agency says it will not release these records until at least October 2017, meaning the question of conspiracy remains open.

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