Author Larry Holcombe claims that aliens played an important in the assassination of John F. Kennedy, in his new book 'The Presidents and UFOs-A Secret History from FDR to Obama.'

The late comedian Jackie Gleason was good friends with President Richard Nixon and both men were obsessed with UFOs, the New York Post reported.

Holcombe, a clear believer, breaks down every rumor about UFO visitation and the government's "involvement" in it. There are many stories of sightings by high-level people, and it's no secret that the government has looked into many of these reports over the years.

While campaigning for president, Jimmy Carter promised, "If elected, he would disclose what the government knew about the UFO phenomenon," however, to Holcombe's knowledge, he never did.

Holcombe believes that Kennedy, who requested UFO data from the CIA, had a great concern that UFOs could be mistaken by the US or the Soviet Union as a nuclear attack, and it was believed he discussed this issue with Soviet leader Nikita Khrushchev.

Holcombe cited a classified CIA communication from the Kennedy era that reads, in part, when conditions become nonconductive for growth in the environment and Washington cannot be influenced any further, it should be "wet."

Since "wet" was Soviet code for "assassination," Holcombe believed that this could be CIA code for a plot to kill Kennedy. Because he was considering telling the world that aliens existed.