Still wondering about the mystery of flying saucers and 3-foot tall aliens dressed in metallic clothing, which the FBI described in a 1950 memo? The agency has released a statement with details about the famous document.

The memo describing the mysterious UFOs was created in 1950, three years after the Roswell incident, but the Federal Bureau of Investigation claims they are not connected. In a blog post published this week, the agency says it never investigated the mysterious sightings – even though it could not explain what Guy Hottel, former head of the FBI’s Washington, D.C. field office, described.

"An investigator for the Air Force stated that three so-called flying saucers had been recovered in New Mexico," Hottel wrote in the memo, which was addressed to FBI Director J. Edgar Hoover. "They were described as being circular in shape with raised centers, approximately 50 feet in diameter. Each one was occupied by three bodies of human shape but only 3 feet tall, dressed in metallic cloth of a very fine texture. Each body was bandaged in a manner similar to the blackout suits used by speed fliers and test pilots.”

According to the document, three men including a police officer, a highway patrolman and an army guard had all reported seeing a “silver colored object high up approaching the mountains at Sardina Canyon” which then “appeared to explode in a rash of fire”. It also explained that several residents had reported witnessing two explosions, followed by a falling object.

The memo had first been released under the Freedom of Information Act in the late 1970s, but was not available online until the FBI uploaded its public records in April 2011. Since being posted to the Internet two years ago, the document has generated more than two million views, making it the FBI’s most-viewed public record in history.

The document’s publication has led to numerous media reports that labeled it as “proof” of alien existence. In 2011, the Daily Mail connected the FBI’s report to the 1947 Roswell UFO incident – an alleged extraterrestrial spacecraft crash that has been the subject of controversy for decades.

But since the FBI’s memo was published three years after the Roswell incident, the agency wants the media to know that it is a separate incident and that it never solved the mystery.

"The Hottel memo does not prove the existence of UFOs. It is simply a second- or third-hand claim that we never investigated,”  the bureau said in a blog post on its website.

"There is no reason to believe the two are connected,” the post added.

Even though it is the FBI’s job to investigate potential security threats, which may include unidentified flying objects and mysterious explosions, the agency has defended its inaction, claiming that verifying UFO sightings is not part of its job description.

“The FBI has only occasionally been involved in investigating reports of UFOs and extraterrestrials,” the blog says. “For a few years after the Roswell incident, Director Hoover did order his agents—the request of the Air Force—verify any UFO sightings. That practice ended in July 1950, four months after the Hottel memo, suggesting that our Washington Field Office didn't think enough of that flying saucer story to look into it.”

Although the FBI wants to clear up rumors about the memo and claims that it never confirmed that any sort of alien life forms had been found, the agency does admit that the sightings still remain a mystery – a statement that might instill hope among UFO believers.

“Sorry, no smoking gun on UFOs,” the agency writes. “The mystery remains…”

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