FAA spokesman Mike Fergus said the agency investigates civil allegations rather than criminal ones. He declined to provide details on the nature of the FAA probe or its possible outcome.
Larimer County Sheriff Jim Alderden has said investigators believe amateur storm chasers Richard and Mayumi Heene called 911 Thursday saying they thought their son, Falcon, was aboard the large helium balloon that floated away from their yard in Fort Collins in a bid to get publicity for a reality TV show.
The balloon landed 50 miles away near Denver International Airport. Some flights had to be changed to a different runway for 20 minutes.
Falcon was found safe at home.
Alderden said he is seeking charges against the Heenes including conspiracy, contributing to the delinquency of a minor, making a false report to authorities, and attempting to influence a public servant. The most serious charges are felonies and carry a maximum sentence of six years in prison.
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Alderden said authorities also would be seeking restitution for the costs of the balloon chase, though he didn't provide a figure.
His office has said it will likely be sometime next week before it forwards its findings to prosecutors to decide on charges.
Richard Heene previously has denied a hoax.
He emerged briefly from the family's home Tuesday morning but didn't answer reporters' questions.
Heene did show two delivery workers where to find five leased helium tanks that were being returned to Flexx Productions, a Fort Collins rental company. The workers said four of the tanks were empty and one was partially full.
An associate of Heene's, Robert Thomas, has told sheriff's investigators that he helped record Heene's ideas for a TV show, said Thomas' attorney, Linda Lee.
"He was very interested in being famous,"Tuesday.
According to Thomas' lawyer, Lee, "Heene believes the world is going to end in 2012... 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."
Thomas told NBC's "Today" show on Tuesday that he had nothing to do with the hoax and didn't know about the balloon being launched until he saw it on television.
Lee said investigators told her Thomas would not face charges but that she was seeking immunity for him "just to be safe." Thomas has said he had no idea that a possible hoax could involve the Heene children.
The Heenes twice appeared on ABC's "Wife Swap," including a March episode in which they discuss their approach to parenting and talk about their belief that they're the descendants of aliens.
The producer of "Wife Swap" had a show in development with the Heenes but said the deal is now off. The TLC cable network also said Heene had pitched a reality show months ago, but it passed on the offer.
Two former associates told "The Early Show" thatto be around at times and had created an unsafe environment for his three sons.
Barbara Slusser, who worked with Heene as a stormchaser and appeared with him in the reality show "Wife Swap" said he could be "a lot of fun" sometimes, but "it could be terrifying at times when he'd go off. It was a three-ring circus."