The eccentric family in Colorado's runaway balloon drama will be questioned to clear up suspicions of a hoax but investigators are convinced they are telling the truth, police said.

Larimer County Sheriff Jim Alderden said while police were adamant that the event that gripped US media on Thursday was real, officers would seek clarification of remarks made by six-year-old Falcon Heene.

Falcon became the focus of a massive multi-agency rescue operation after he was initially believed to have floated away on a homemade helium balloon built by his father for a weather experiment.

Heene was later discovered hiding in the attic of his garage to the relief of investigators and the boy's family. But Falcon fueled skepticism about the incident during an interview with CNN's Larry King Live late Thursday.

Asked by his father, Richard Heene, why he had not come out of his hiding place sooner, Falcon replied: "You guys said that we did this for the show."

The remark was swiftly seized upon by commentators and bloggers as evidence of a hoax, suggestions Richard Heene angrily denied Friday.

Asked on NBC television's "Today" show Friday if the incident had been a hoax, Heene replied: "Absolutely not. Absolutely not. And now I'm starting to get a little bit ticked off I'm repeatedly getting asked this in interviews.

"What have I got to gain out of this? I'm not selling anything, I'm not advertising anything."

Yet the Heenes' media offensive appeared to be taking its toll when Falcon vomited live on national television in separate interviews.

Police chief Alderden said the Heene family would be re-interviewed, probably on Saturday, but stressed during a press conference on Friday that investigators believed they had not been hoaxed.

"We were convinced yesterday after talking to the parents and having investigators on scene during the duration of this event that the parents were being honest with us," Alderden said.

"They appropriately expressed statements, non-verbal communication, body language, and the emotions during this event that were entirely consistent with the events that were taking place."

"We believe at this time that this is a real event," Alderden said.

When the balloon finally made a soft landing and Falcon was not inside, the Heene parents had shown a "significant deflation of their emotional state which our people did not think could be faked or was being faked," he said.

Alderden said it was "inconceivable" that Falcon could have been "coached" by his parents to stay silent in his attic hiding place for hours.

"It seems much more likely that the boy was in fact frightened because he somehow thought he was responsible for this device becoming untethered and therefore decided to hide," he said.

Alderden also noted that Falcon's parents had freely allowed investigators to interview their son in private after his discovery.

However, he acknowledged that the youngster's remark to CNN had "raised everybody's level of skepticism." "We feel it is incumbent upon us to go back to the family and interview them to establish whether in fact this is a hoax or if it is an actual event," he said.

Alderden said if the Heenes had faked the episode they could face misdemeanor criminal charges and demands to pay for the costs of the aborted rescue operation. "If there is criminal conduct, we will seek restitution," Alderden said.

Yet the Heene family's colorful hobbies -- they appeared on a reality television show, build wacky inventions and chase after powerful storms -- has left many convinced that the balloon story is a fake.

A former associate of Richard Heene told ABC television he believed the incident had been faked.

"I believe that Richard had a plan to send this craft aloft," said Scott Stevens, who used to work as a "storm chaser" with Heene. "Whether it was to leave the illusion that there was a boy on board, I don't know."

Other media commentators were not sure what they had witnessed.

"Did life imitate art or did art imitate life or is it possible anymore to tell the difference?" Denver Post columnist Mike Littwin wrote.