FORT COLLINS -- A former research assistant says Richard Heene was plotting a publicity stunt using a UFO-shaped balloon and "some controversy" to feed his obsession with reality TV stardom.

Larimer County Sheriff Jim Alderden is investigating Heene and his wife, Mayumi, for a criminal conspiracy to fool authorities into believing their 6-year-old son was adrift in a runway silver saucer balloon Thursday.

Millions worldwide watched the drama on live TV as helicopters and cameras tracked the balloon until it softly crashed in a field. Young Falcon Heene was later found to be hiding in the attic of the family's Fort Collins garage.

The sheriff said investigators want to speak with the Robert Thomas, the 25-year-old former Colorado State University student who was paid by Gawker.com for the exclusive expose titled: "I Helped Richard Heene Plan a Balloon Hoax" -- which appeared on the Web site Saturday.

"We are aware of Mr. Rob Thomas. We have been unable to locate Mr. Thomas," Alderden said at a Sunday morning press conference. The sheriff said investigators have evidence that the "Balloon Boy" melodrama "was a publicity stunt done with the hopes of marketing themselves, or better marketing themselves, for a reality television show at some point in the future."

7NEWS could not reach Thomas Sunday.

Thomas said he worked for Richard Heene who was feverishly laboring to launch a "Science Detectives" reality-TV show deal that would be along the lines of "MythBuster-meets-mad scientist."

While talking about their mutual interest in UFOs earlier this year, the men hit on the legendary 1947 crash of an object in Roswell, New Mexico, which spawned conspiracy theories and pop TV shows that an alien creature's remains were recovered and concealed by the government.

"How much do you want to bet we could facilitate some sort of a media stunt that would be equally profound as Roswell, and we could do so with nothing more than a weather balloon and some controversy?" Richard Heene said, according to the Thomas account on Gawker.com. Thomas said two other unidentified people were working on the reality-TV proposal.

"We will modify a weather balloon, so that it resembles a UFO," Heene told Thomas, according to Gawker. Com. "We will capture the footage on film, and will utilize the media as a means ... to make our presence known to the masses. This will not only provide us with incredible footage, but will also generate a tremendous amount of controversy among the public, as well as publicity within the mainstream media."

"The result will be a dramatic increase in local and national awareness about The Heene Family, our Reality Series, as well as the UFO Phenomenon in general," Thomas recounted Richard Heene saying, according to Gawker.com.

"I clearly remember Richard telling me that, if we accomplish this, it would be the most controversial and widespread UFO news story since Roswell in 1947," Thomas said.

Thomas, who got involved with Richard Heene because of their mutual fascination with science experimentation, said he became delusioned when Heene, who had appeared with his wife and young sons on the reality show "Wife Swap" earlier this year, became increasingly "driven by ego and fame."

"He wanted nothing more than to get another reality TV series," Thomas said.

Other business associates also describe Heene as a man with burning ambition, mercurial moods and a fascination for conspiracy theories.

"He liked listening to some of the conspiracy theories -- UFOs or aliens. He also thinks that 9/11 is probably an inside job," said Vince LeGrow, a former employee who bought Heene's Los Angeles production company, which made audition tapes for actors, in 2007. Heene then relocated his young family to Fort Collins, where the balloon incident occurred.

"He had his ups and downs," LeGrow said of Heene, who met his future wife, Mayumi, when the two were aspiring actors at the famed Lee Strasberg drama school in Hollywood.

"If he's upset about something he can get really upset. I've seen him throw things," LeGrow recounted. "But when he's happy about something, he's super happy, does cartwheels."

But in recent months, Thomas said Heene became financially strapped and increasingly obsessed and paranoid about selling his reality show and about dark new-age predictions that the world will end in 2012. Heene's day-job is home remodeling.

Fears about the looming apocalypse, supposedly foretold in ancient Mayan calendars, has spawned a new Hollywood adventure film, titled "2012," about a global cataclysm. It's also fueled 2012 "survival groups" in Europe, Canada and the United States.

"As the weeks progressed, his theories got more and more extreme and paranoid," Thomas told Gawker.com. "A lot of it surrounded 2012, and the possibility of there being an apocalyptic moment. Richard likes to talk a lot about the possibility of the sun erupting in a large-scale solar flare that wipes out the earth."

"It got to the point where he was really pressing me, saying ,'We're running out of time, we're running out of time, the end of the world is coming. And we have to take necessary precautions to make sure that we're not among the majority that's going to be killed,'" Heene told Thomas, according to the Web site.

Thomas said he knew nothing about involving Heene's young son in the publicity stunt. Then he got a call Thursday from a friend saying "Rob, you need to turn on the TV immediately! That Richard guy you worked with just pulled a massive publicity stunt!"

"My doubts and concerns about that story were verified when Falcon's parents asked him on CNN, 'Why didn't you come out?' And Falcon said, 'You guys said we did this for the show,'" Thomas told Gawker.com.

"Lights went off in my head, bells were ringing ... I said, 'Wow, Richard is using his children as pawns to facilitate a global media hoax that's going to give him enough publicity to temporarily attract A-list celebrity status and hopefully attract a network,'" Thomas said.