Prosecutors build case against balloon hoax family

US investigators pored over emails, phone records and financial documents from the home of Richard Heene as they weighed felony charges and sought to determine who else might have helped the alleged balloon-boy hoax get off the ground.

The sheriff's office said its findings will be forwarded to prosecutors next week to decide if Richard and Mayumi Heene should be charged with falsely reporting that their six-year-old child had drifted away in a large home-built helium balloon to drum up publicity for a reality TV show.

The boy, Falcon, was never in the flying saucer-shaped balloon, which flew unmanned for 50 miles last Thursday, in a story that played out live on national television. His family said they discovered he had been hiding in the family's garage.

The investigation could reach beyond the Heenes, possibly into the world of reality-show promotions.

Larimer County Sheriff Jim Alderden said documents show that a media outlet had agreed to pay the Heenes.

Mr Alderden did not name the organisation but said it was in an industry that blurs "the line between entertainment and news".

It was not clear whether the deal was signed before or after the alleged hoax, or whether the media outlet was a possible conspirator. If so, the organisation could face charges as well.

The Heenes are amateur storm chasers who apparently wanted to star in a reality show that focused on a range of absurd experiments, such as attracting UFOs with a weather balloon, launching a model rocket into space and conducting an electromagnetic analysis of a terminally ill patient's spirit before death.

Robert Thomas, a collaborator who worked with Richard Heene on the idea, provided an e-mail to the website Gawker.com outlining his plan for the show.

The sheriff's department questioned Mr Thomas on Sunday night after he revealed that Heene was planning a media stunt to promote the show, according to the researcher's lawyer, Linda Lee.

Mr Thomas' notes include Heene discussing a hoax - which Mr Thomas opposed - that involved a hot air balloon, Ms Lee said.

"Pretty much he wanted to recreate this Roswell effect making it seem like there's a UFO," Ms Lee said.

In 1947, the US military said a weather balloon crashed near Roswell, New Mexico, in the desert, but legends persist that it was a UFO.

"Heene believes the world is going to end in 2012," she said.

"Because of that, he wanted to make money quickly, become rich enough to build a bunker or something underground, where he can be safe from the sun exploding."