FORT COLLINS, Colorado — The parents who set off a worldwide drama by reporting their 6-year-old son was inside a flying saucer-like helium balloon hurtling over Colorado concocted the stunt to market themselves for a television show, a sheriff said Sunday.

Larimer County Sheriff Jim Alderden said no charges had been filed yet, and the parents weren't under arrest. He said he expected to recommend charges of conspiracy, contributing to the delinquency of a minor, making a false report to authorities and attempting to influence a public servant.

Some of the most serious charges each carry a maximum sentence of six years in prison and a $500,000 fine. The sheriff said if charges were filed, his office would seek restitution, but he didn't know the total cost of the rescue effort, which included military helicopters, a ground rescue and even a mounted posse. Officials also rerouted planes around the balloon's flight path and briefly shut down some flights from Denver International Airport.

Alderden said the parents Richard and Mayumi Heene "put on a very good show for us, and we bought it."

Alderden said at an extraordinarily candid news conference that the boy, Falcon Heene, may not have even been hiding in the rafters of the family's garage during the intense five-hour search for him Thursday afternoon.

"For all we know he may have been two blocks down the road playing on the swing in the city park," the sheriff said.

Richard and Mayumi Heene were shopping at a Wal-Mart with their three sons as Alderden told reporters at the sheriff's station that the whole thing was a hoax.

Richard Heene said he's "seeking counsel," though it was unclear whether he was talking about hiring an attorney.

"This thing has become so convoluted," Heene told The Associated Press as tears welled up in his eyes.

He said his wife was holding together better than he was.

The sheriff said all three of the Heenes' sons knew of the Thursday hoax, but likely won't face charges because of their ages. The oldest son is 10. One of the boys told investigators he saw his brother get in the balloon's box before it launched.

Heene, a storm chaser and inventor, and his family have appeared on the ABC television reality show "Wife Swap." Alderden said the couple met in acting school in Hollywood. Richard Heene has described himself as an amateur scientist, but Alderden said Heene has only a high school education.

"He may be nutty, but he's not a professor," Alderden said, adding Heene showed "no evidence of remorse" for the episode.

Alderden said interviews with the parents Saturday resulted in enough information to get a warrant to search the house. He said they were looking for computers, e-mails, phone records and financial records.

Alderden said the children were still with the parents Sunday morning, and child protective services had been contacted to investigate the children's well-being.

Alderden said the "aha moment" came when, during a Thursday night interview with CNN, Falcon turned to his dad and said what sounded like "you said we did this for a show" when asked why he didn't come out of his hiding place.

"If you look at the nonverbal responses, as well as some of the verbal cues, not only for him but from the family, the children, their reaction, it became very clear to us at that point that they were lying," Alderden said.

On Friday, Falcon got sick during two separate TV interviews Friday when asked again why he hid.

Alderden was asked whether officials had concerns for Falcon's safety.

"Clearly, from all indications, Mr. Heene has somewhat of a temper," Alderden said.

Alderden said officials tried Saturday to persuade Mayumi Heene to go to a safe house, but she declined.

"We talked to her at length about domestic violence, about her safety, about her children's safety," the sheriff said. "We have a concern, but we didn't have enough that would allow us or child protective services to physically take the kids from that environment."

A Colorado State University physics professor, using dimensions given by Richard Heene, had told sheriff's officials as they were tracking the balloon Thursday that it was plausible for it to lift off with 37-pound (17-kilogram) Falcon inside.

Once the device landed, sheriff's officials discovered it was made with plastic tarps taped together and covered with aluminum foil, with a utility box made of a very thin piece of plywood, cardboard on the side, held together with string and duct tape, Alderden said.

Using the true dimensions, the professor determined it could not have launched with the boy inside, Alderden said.

Alderden said the alleged hoax had been planned for at least two weeks and that investigators suspect that other individuals and a "media outlet" that he would not name were in on it.

"We do understand, looking at some of the documents already, that at least one of the media outlets has agreed to pay them some money with regards to this particular incident," Alderden said.

He said he was not talking about a news organization, but "there are so many of these shows that kind of blur the line between entertainment and news."

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