SACRAMENTO (CBS13) – On Friday Nov. 22, 1963, less than an hour after he had arrived in Dallas for a rally, President John F. Kennedy was gunned down.

Now, 50 years later, we’re hearing from a man who’s dedicated his entire life to figuring out what really happened that day, and he says he knows the truth.

“I smelled a rat,” said William Turner.

He has seen it more times than he cares to count. The grainy Zapruder film captured a pivotal moment in American history — the shot seen and heard around the world.

President Kennedy was shot in the head and rushed to a Dallas hospital. There was nothing doctors could to do save him.

Turner saw the aftermath first hand, arriving in Dallas just hours after the assassination.

“It was a somber and eerie situation,” he said. “It was half dark and people were crying.”

Turner was a G-Man — an FBI agent from 1951 to 1961 — with counter espionage and major crime cases his specialty.

However, He grew increasingly concerned by the way J. Edgar Hoover was running the bureau. Hoover found out and cut Turner loose.

So, he parlayed his investigative talents into becoming a journalist. His very first assignment was to head to Dallas to cover the breakdown of security during the assassination.

He scoured Dealey Plaza, asking questions, and using former FBI colleagues as confidential sources.

“I conducted the investigation and had two pieces of information that I thought might be pertinent,” Turner said.

Witnesses, including a police officer, told him they thought there was a second shooter.

“He thought he heard three shots from an upper area equally spaced,” said Turner. “A woman ran up to him from the direction of what we now know as the Grassy Knoll and the bushes there, and said ‘they were shooting from the bushes.’ ”

The Warren Commission concluded in the official government report there was a lone gunman — Lee Harvey Oswald.

“The bushes are a good distance from the supposed sniper perch of Oswald,” said Turner. “I tucked that in my bonnet and it demonstrated there were at least two shooters.”

Turner was one of the first to report that. Days then turned to hours, which turned to decades. A lifetime of research led Turner to a shocking conclusion — the Kennedy’s murder was choreographed by our own CIA.

“I think what happened was a capacity for assassination was set up by (a) CIA base in the Everglades called Point Mary. That’s where they trained Cuban snipers,” said Turner.

He says two of those Cuban snipers were sent to assassinate the president. The CIA and Kennedy had a falling out after the 1961 Bay of Pigs invasion in Cuba. After the failed plan to oust Fidel Castro, it’s reported that Kennedy promised to smash the CIA into a thousand pieces.

But would the CIA really plot to kill a U.S. president?

“I believe the mafia was allied with the CIA in assassinating Kennedy, and I think we’ve proven that and should go ahead with closure — designating it a conspiracy and not a single man’s work,” said Turner.

It’s a tangled web. Turner believes President Lyndon B. Johnson worried a full investigation could reveal plans to assassinate Castro — a finding he feared could escalate into a nuclear war with Cuba and their soviet allies.

“National security is used as an excuse for all kinds of ridiculous activities and the failure to investigate the assassination of JFK was one of their worst failures,” said Turner.

He says there was one thing that kept him going all these years.

“I’m known as being very stubborn. I think that explains it all,” said Turner.

JFK experts credit Turner for the Cuban connection and the release of scores of once-top secret documents.

Although Turner doesn’t believe Americans will ever know the whole truth, even after 50 years in search of it, he has he wants those seeking to know.

“Keep the faith,” he said.