The document is said to have been given to Heather Wade, host of US late-night online paranormal radio show Midnight in the Desert, from a known source who has not been named.
Many UFO experts have branded the document fake, but the release has set the conspiracy theory world on fire, with others convinced it could be genuine.
The document claims a highly secretive team of top scientists, government officials and military leaders – all now dead – was set up in the wake of the Roswell incident to investigate the “captured flying sauce remains” and “four dead aliens” and assess the risk to the planet of “visiting aliens“.
The document claims the group was called Majestic 12 and set up on the orders of President Harry S Truman, in the wake of Roswell.
US ‘hiding 7 flying saucers and 27 alien corpses – alleged DIA leak
Four decomposed aliens were found 2km from the Roswell crash site
*Detlev Wulf Bronk, another US scientist, educator, who died aged 78 in 1975, and was recognised for developing biophysics as an established science.
*Vannevar Bush, an American engineer and inventor and science, who led the US Office of Scientific Research and Development during World War II.
It carried out military research and development. He died aged 84 in 1974.
*Donald Howard Menzel, who died in 1976 aged 75, who was one of the first theoretical astronomers and astrophysicists in the US, and discovered the physical properties of the solar chromosphere, the chemistry of stars, the atmosphere of Mars, and the nature of gaseous nebulae.
*Hoyt Sanford Vandenberg, a US Air Force general, its second Chief of Staff, and second Director of Central Intelligence, who died in 1954 aged 54.
*Nathan Farragut Twining, who died in 1982 aged 84, who was Chief of Staff of the United States Air Force from 1953 until 1957, and during the Roswell UFO incident.
ROSWELL: What is said in alleged DIA ‘UFO and alien leaked report’?
*James Vincent Forrestal, who died in 1949 aged 57, and was the first United States Secretary of Defense.
*Gordon Gray, who died in 1982 aged 73, who was a defense and national security government official.
*Roscoe Henry Hillenkoetter, the third director of the post-World War II United States Central Intelligence Group (CIG), who died aged 85 in 1982.
*Jerome Clarke Hunsaker, who died aged 98 in 1984, and was from 1941 to 1956 chairman of the National Advisory Committee for Aeronautics.
Seasoned UFO expert and nuclear physicist Stanton Friedman is investigating the authenticity of the document and is said to believe it could be genuine.
The Paridigm Research Group (PRG) which tries to pressure the White House to disclose documents about UFOs believes the report could be genuine, but accepts it could also be fake.