THE two men involved in one of the most bizarre ‘alien’ encounters on record recalled seeing "creatures with slit-like mouths and crab pincers" while under hypnosis, top secret files obtained by Sun Online reveal.

Charles Hickson and Calvin Parker claim they were captured by three alien creatures and taken into a UFO while they were fishing in Pascagoula, Mississippi, on October 11, 1973.

Now never-seen-before handwritten notes of a secret interview conducted on them under hypnosis reveal how they both described strange creatures looking like robots with unusual eyes, grey skin and crab pincers for arms.

The interview was conducted in 1973 by case investigators Professor J Allen Hynek and Dr James Harder - and the terrified men’s account was enough to convince the pair that they were telling the truth.

Dr Harder’s files include notes from the interview and other information he gathered - and offer a unique insight into the infamous sighting almost 45 years ago.

On one handwritten page Dr Harder writes: “I asked what the ‘creatures’ looked like and got a description which included 1. No neck, no helmet 2. crab-like hands, two digits … 3. slit-like ‘mouth’.”

The beings did not communicate and had a “robot businesslike attitude”, the men recalled during the hypnosis session.

Charles, 42, and Calvin 19, were sat on the banks of the Pascagoula River, when they claim they heard a whizzing sound overhead.

They said that an oval shaped "craft", some 8ft across, suddenly appeared near them and seemed to levitate about 2ft above the ground.

A door opened and three creatures - who were "humanoid" in shape and about 5ft tall - emerged and seized the men, "floating" them into the UFO, they later told police.

Both men reported being paralysed and numb - while Calvin claimed that he had fainted due to fright.

The men said the creatures had claws at the ends of their arms, "carrot-like" growths for their nose and ears, and only one leg.

One page of Dr Harder’s handwritten notes states: “Key novel features - 1. Cessation of sensation upon contact. 2. “floating” them along one foot from the ground. 3. Crab-like arm appendages. Two ‘pincers’ of equal size.”

There was a “possible suggestion” they were “robot” due to their “lack of usual eye structure, pincers on arms and “possible fused lower ‘limbs’” according to the notes.

“After they touched them they felt nothing but weightlessness,” the doctors’ notes read.

On the ship, Charles claimed that he was examined by what looked like a large football-shaped mechanical eye, about 6 to 8  inches in diameter, that seemed to scan his body.

Calvin claimed that he could not recall what had happened to him inside the craft.

The men said they were released after about 15-20 minutes and the creatures levitated them, with Charles's feet dragging along the ground, back to their original positions on the river bank.

In another page of the notes, Dr Harder said attorney Joe Colingo described the men as looking "scared to death" and "as frightened as any two adult human beings as I've ever seen."

Philip Mantle, a former director of investigations for the British UFO Research Association, managed to obtain the file containing the handwritten notes during his research.

However - in a bizarre twist - he says that many of Prof Hynek’s and Dr Harder’s other notes and tapes from the case are mysteriously missing.

Hynek was a consultant to top secret UFO studies by the US Air Force including Project Blue Book (1952–1969). He initially started as a skeptic but went on to found the Centre for UFO Studies in 1973.

The astronomer also coined the phrase 'Close Enounters of the Third Kind' which was used as the title of Steve Spielberg's $20million blockbuster about UFOs in 1977.

His files were spread out between Northwestern University, the Centre for UFO Studies while Dr Harder's were kept at private facilities.

But Philip claims that dozens of boxes related to the case have vanished.

Philip, who has published the book Pascagoula - The Closest Encounter written by Calvin Parker, said: "No one knows who took these files.

"Were they taken deliberately, part of a possible cover-up? Or could they simply be lying in a collector's attic somewhere?

"The fact is that no one knows but we do know that these files and documents did exist and we are confident that they are 'out there' somewhere.

"We are asking anyone out there who might have these documents and files or may know of there whereabouts, or may have even been a witness themselves to the event, to please come forward.”