'Balloon boy' incident was hoax, sheriff says

(CNN) -- Three days after the world watched a giant balloon fly through the air as a tearful family expressed fears that their 6-year-old boy could be inside, authorities announced what millions already suspected: The whole thing was staged.

The "Aha!" moment that led authorities to realize what had happened was an interview with the family Thursday night on CNN's "Larry King Live," Sheriff Jim Alderden of Larimer County said Sunday. In the interview with Wolf Blitzer, filling in for King, the Heenes asked their son why he had not come out from hiding when they called his name.

"You guys said we did this for the show," the boy responded.

On Sunday, Alderden called the incident a "hoax," adding that investigators believe the evidence indicates that "it was a publicity stunt" by the family in hopes of "better marketing themselves for a reality television show at some point in the future."

The parents, Richard and Mayumi Heene, met in a Hollywood acting school and "put on a very good show for us," Alderden said. Authorities know there was "a conspiracy" between them, he added.

The sheriff's announcement included an admission that authorities misled the media on Friday when they said they still believed it was not a hoax. After Falcon's remark on CNN Thursday night, "it became very clear to us at that point that they were lying," Alderden said.

The "nonverbal responses" and "verbal cues" from the children at that moment made it clear, Alderden said.

But in order to get to the truth, "it was very important during this time that they maintained their trust with us." So investigators misled the media while they carried out their "game plan" of gathering the truth. Watch Alderden tell how police recognized "hoax" »

That plan included pursuing separate interviews with the Heene parents and polygraph tests, partly by arguing that it could help end the media frenzy surrounding them, Alderden said. He added that by law he could not say whether those tests were taken.

The Heenes have repeatedly denied any hoax. In an interview Friday with CNN's "American Morning," Richard Heene said Falcon's remark was a reference to the media that had assembled in front of the family's home.

The Heenes had no immediate response to Sunday's announcement.

Charges have not been filed, but authorities expect to recommend felony charges including conspiracy, contributing to the delinquency of a minor and attempting to influence a public servant, Alderden said. They also plan to recommend a charge of filing a false police report, which is a misdemeanor.

He also said it is unlikely that someone convicted of these charges would face jail time.

One of the key questions that remain unanswered, Alderden said, is: Where was Falcon as police searched for him? On Friday, Alderden said it had been determined that the boy was hiding in an attic in the garage, and had fallen asleep. Now, authorities are unsure. Alderden said the boy may not have even been in the home. Watch body language expert analyze Heene interview »

"The biggest error we made is when we searched the house, very clearly we didn't search the house as thoroughly as we should," he said. Authorities had assumed a 6-year-old boy could not have reached that attic, he said, so they took the Heenes at their word that he had hidden there the whole time.

The Heenes have previously appeared on the ABC program "Wife Swap." Richard Heene chases storms and brings the family along.

After the Hollywood gossip Web site TMZ.com reported that the Heenes had been "pitching a reality show about the wacky family," one of the networks mentioned -- TLC, which produces the show "Jon and Kate plus 8" -- told CNN that "they approached us months ago, and we passed."

Heene has been described as a meteorologist, but his education ended at the high school level, Alderden said. Explainer: How 'balloon boy' drama began »

Alderden also said authorities are concerned about the safety of the three children, ages 6, 8, and 10. In fact, authorities spoke with Mayumi Heene "at length about domestic violence" and the children's safety, Alderden said. "But we didn't have enough that would allow us or Child Protection Services to physically take the kids from that environment."

There was a 911 call from the home earlier this year that led authorities to a "suspicious circumstance" that Alderden said may have involved "domestic violence, perhaps against the wife."

In an interview Friday with CNN's "American Morning," the Heene parents -- looking exhausted -- expressed relief that their son was alive. "I'm feeling very, very grateful that Falcon is among us," Richard Heene said.

Mayumi Heene said that the family was sitting in their living room, distraught and terrified for missing Falcon, when he walked into the room.

"[It] felt like from nowhere. When I first saw him, I couldn't even believe it. I couldn't comprehend right away," she said, adding that the next moment she was "just jumping, calling his name." She began to "scream and cry, and I just enjoyed that moment."

CNN's Greg Morrison and Janet DiGiacomo contributed to this report.

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