GETTY•NASA JFK (right) on a NASA visit six days before his murder over a mock-up UFO sighting

The claim was made after US presidential Democratic candidate Hilary Clinton vowed to get to the bottom of an alleged UFO cover up high within the government. Scott C Waring, editor of UFO Sightings Daily, posted copies to his website of a letter sent by JFK to the then head of the CIA just 10 days before he was murdered. He wrote: "Presidential candidate Hillary Clinton doesn't know it yet, but she does not have the power to release such information. "CIA would kill her before she could, just like they did JFK. "Yes, just a week before his death JFK wrote a memo to CIA to release all pertinent info to NASA, but somehow he was killed before it ever happened. "I was the first to publish this document in my book UFO Sightings 2006-2009." The memo is a confirmed declassified document released by the CIA. Mr Waring added: "JFK wrote the memo to CIA on Nov 12, 1963, then on Nov 22, 1963 he was killed. "Hillary will be too scared of the CIA to release such information."

CIA•IG The now declassified but redacted memo from JFK to then head of CIA 10 days before his death

The memo asked for a breakdown of identified and unidentified sightings the CIA was aware of. JFK wrote: "It would be very helpful if you would have the high threat cases reviewed with the purpose of identification of bona fide as opposed to classified CIA and USAF sources. "It is important that we make a clear distinction between the knowns and unknowns in the event the Soviets try to mistake our extended cooperation as a cover for intelligence gathering of their defence and space programs. "I would like you to arrange a program of data sharing with NASA where unknowns are a factor." On the same day JKF sent a separate memo to NASA asking for "cooperation with the former Soviet Union on mutual outer space activities." It is understood JFK was concerned about the high amount of UFO sightings over Russia and feared the Soviets would wrongly believe it was US spying equipment. Four days later on November 16 1963 he visited NASA at Cape Canaveral, Florida, which further fuels the conspiracists theory.

NASA•BOBPATY•BILLBRIDGES JFK (centre) during the NASA visit at the Saturn Blockhouse

Presidential candidate Hillary Clinton doesn't know it yet, but she does not have the power to release such information. CIA would kill her before she could, just like they did JFK Scott C Waring

Several other alien researchers have said they support the theory on various postings on websites. In the 1990s a document which became known as the "burned memo" surfaced. It was allegedly received in the post by a UFO researcher called Timothy Cooper in 1999 and was said to have been sent by an unnamed CIA source who allegedly worked three from 1960 to 1974. The alleged source claimed the document, which has never been verified as real, was pulled by him from a fire while the CIA was burning sensitive material, hence the scotch marks. The memo had no date and referred to "Lancer", the supposed secret service code name for JFK. It allegedly had this message from the director of Central Intelligence: "As you must know, Lancer has made some inquiries regarding our activities, which we cannot allow. "Please submit your views no later than October. Your action to this matter is critical to the continuance of the group." Sceptics claim the "burned memo" was a fake to add fuel to the conspiracy. There have been many conspiracies surrounding JFK's death, including those claiming CIA involvement, but not always because of UFOs.

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