The account filmed in 1999 was released in the book UFOs TODAY, 70 Years of Lies, Misinformation and Government Cover-Up by Dr Irena Scott in June.
British UFO investigator Philip Mantle, who published it, says he was criticised by others in the field for releasing the video, amid claims it was a “false testimony”.
UFO crash site? Charles Forgus pictured with his wife.
But the following day it retracted the statement, saying it was in fact a damaged US Air Force air balloon.
Witnesses later came forward to say there had been alien bodies within the “crashed craft”, which along with the wreckage were then taken to a mysterious top-secret military base.
All the confusion means it is one of the world’s biggest conspiracy theories to this day.
Mr Forgus described hearing about the crash site on police radio while he and Sheriff Jess Slaughter were enroute near Roswell to pick up a prisoner.
He said the pair took a detour to view it and saw a flying saucer on the ground and mysterious bodies being removed.
Yet, another investigation by the US-based Mutual UFO Network (MUFON) concluded he may have witnessed a crash six years later involving a US Air Force training flight and nothing to do with aliens.
DEAD ALIENS? A CGI impression of the UFO crash site.
Due to timescale discrepancies, it was deduced he may have seen a different crash.
It was found that Mr Slaughter, the sheriff named by Mr Forgus, was not the sheriff in 1947. He took on the role in the 1950s.
And Mr Forgus did not become deputy until 1953, records show.
Articles in the Big Springs Weekly Herald were found that had been published about Sheriff Slaughter and Deputy Forgus in 1953.
MUFON investigator Robert Spearing was not convinced Mr Forgus saw the Roswell UFO crash, but may have been at the site of a US Air Force crash in 1953.
Mr Spearing found an article in the Reno Evening Gazette dated August 28, 1953, which said 11 airmen had survived a crash in a B-50 bomber which landed wheels up on gently rolling plains 35 miles southwest of Tatum, New Mexico.
Mr Spearing said in a MUFON investigation report: “This would coincide with their westward trip shortly before they turned north to Roswell.”
However, he said this crash conflicted with the account of Mr Forgus as it was not disc shaped and there were no dead bodies.
UFO CRASH? A possible crash site near Roswell as described by Charles Forgus.
He concluded: “It seems highly unlikely that Mr Forgus was forging a story from untruths.
“His time frame is off but it seems likely that he came across something unusual in the desert along with Mr Slaughter.
“It also seems more likely that the event occurred in 1953 when the US military was experimenting with Vertical Take Off Landing (VTOL) disc shaped craft some of which were 100 feet in diameter and probably piloted by one or two airmen.
I can tell you, he is not a person who would have fabricated this story.
However, MUFON was unable to speak to any relatives of Mr Forgus.
But, after the story broke in June, Mr Mantle and Dr Scott were able to track down Mr Forgus’ son, Glen Lee Forgus.
Mr Forgus junior revealed that his dad had previously talked about seeing the crash on around four or five occasions.
Mr Mantle said: “He spoke about it to Glen when Glen was young.
UFO TRUTH? The account was revealed in book UFOs Today.
However, his son said his father didn’t talk about seeing bodies.
Mr Mantle added: “At first, he did not necessarily think it was a UFO, Glen said that at that time he may have had no idea what it was.
“Charles might have not thought about UFOs when he first saw the crash, because he hadn’t been exposed to much or even any information about UFOs.
“Later when he heard in the media about UFOs and Roswell, he thought this might have been what it was.”
Mr Mantle added: “Glen also said that he thought that when Charles made the trip to Roswell that he didn’t go with Sheriff Slaughter but with a different person, who might have been another deputy.
“Thus, the crash might have happened in 1947, which was the time that Deputy Forgus recalled that it was.
“Glen said that Charles was a very straight arrow and not impressed by false knowledge. He was a no-nonsense type of person, having been in law enforcement. He had been a police officer and in the military.
“Thus the possibility exists that deputy Charles Forgus did see the crash in the time frame that he reported.”
He said his uncle never mentioned the crash, but added: “I can tell you, he is not a person who would have fabricated this story.”
Mr Mantle said: “He was very straight laced and no nonsense type of person… that’s why he was in law enforcement.
“One well-known Roswell researcher simply labelled the testimony from Deputy Forgus as a lie. Now, we have information from a nephew and the son of this witness the latter of whom supports his late father’s story.”