After our story aired, UFO researchers re-opened the investigation. Here's what they've discovered.

The military says it was a skyhook balloon. But now, more than 58 years after the tragedy, new information has researchers saying the balloon theory is just not possible.

Francis Ridge says, "Something that had been written off for 58 years, all of a sudden became a hot topic."

What was Captain Thomas Mantell really chasing in January of 1948 when he flew his F-51 fighter to an altitude with no oxygen, forcing him to crash to his death in Simpson County, Kentucky?

"The discussions were going wild on the Internet, and people were digging up new information and were finding new evidence," he continues.

Was it a UFO or a skyhook balloon?

That new evidence has now become clear to UFO researchers, like Mt. Vernon's Francis Ridge, who is with the National Investigations Committee on Aerial Phenomenon.

"Where the skyhook was eventually found to be, Mantell could not have seen it, and if he had, of course, it wouldn't have been anything like what he reported," says Ridge.

In a tape recording, Thomas Mantell says, "Mantell to tower. It appears to be a metallic object, and it's of tremendous size."

Ridge says the military's skyhook theory is impossible because official bluebook records show that there was a balloon, but it was hovering over Nashville, some 150 miles away. Those facts are documented by an astronomer who reported seeing it that day.

New reports from the official bluebook archives indicate that Mantell wasn't the only one who saw the UFO that day. So did Kentucky State Police.

Documents state, "Kentucky State Police had sighted an unusual object or aircraft flying through the air, circular in appearance, approximately 250-to-300 feet in diameter moving at a pretty good clip."

That information was relayed to Godman Air Force Base military personnel, and then dispatched to Mantell and three other pilots to investigate.

Three planes turned back because of a lack of fuel and oxygen. Mantell continued his pursuit.

Thomas Mantell, recorded audio, says, "Mantell to tower. I see it above and ahead of me. I'm still climbing."

Shortly thereafter, Mantell went down in a field in Simpson County, Kentucky.

To this day, former Kentucky National Guard Commander Brigadier General Edward Tonini, now living in Louisville, is sticking to the skyhook balloon theory.

He says, "It was unexplained to him certainly what it was, and he was chasing something and not just an illusion. And I believe that it was just this balloon."

The commander of the Kentucky Air National Guard at the time of the incident, retired Two-Star General Phillip Ardery, agrees.

General Ardery states, "It doesn't seem to be much of a mystery to me. We pretty much know what happened."

UFO researchers aren't surprised to hear the military's stance.

Ridge says, "It's natural for the military people to defend what they're told."

But Ridge says his new evidence should change the military's position and dismiss the skyhook balloon theory once and for all.

"They didn't know then what we didn't know a few months ago, and know now it was impossible for that to be," continues Ridge.

Finding the truth hasn't been easy for researchers, who are now investigating the actual accident, but it's not complete.

"This is the accident report. It was supposed to be 450 pages; then, it turned out to be 250 pages, and when we finally got it, it was 127 pages. What happened to the other pages, and what's on those missing documents?" demands Ridge.

(Note: This is probably an error made by UFOlogists, rather than actual missing documents. We caught it early but the interview was filmed three weeks prior to the showing. The accident report in its 127 version was still full of surprises and we're not finished with our analysis. - Ridge)

That's what researchers want to know, and what they will continue to investigate.

Ridge says, "There's more to this case, and thanks to WFIE and Drew Speier, we're getting more and more all the time. We're going to stick with it; we're not done with it by any means."

The Mantell directory

has grown tremendously since our first report. The NICAP team believes that while they admit there was a secret skyhook project, the balloons were no secret. And they proved that the balloon they say Mantell was chasing, could not have been possible.

What they don't know is what Thomas Mantell was chasing to the point where he'd become the first person in history to die while pursuing a UFO. That's something they'll continue to investigate.