Police were to reinterview a Colorado couple last night as speculation mounted that the balloon drama which sparked a frenzied search for their six-year-old son was a huge publicity stunt.

By all accounts, Richard Heene is an unapologetic self-promoter whose off-the-wall activities have included flying saucers, mountaintop helicopter stunts, storm chasing and reality TV shows.

Now, many suspect Heene hid his son Falcon in the rafters of the garage in Fort Collins for five hours to make it seem as if the boy had floated away in a home-made helium balloon.

Thursday's balloon drama unfolded live on television before Falcon was found.

Heene vehemently denied that the events were a hoax, dismissing the claims as "extremely pathetic".

The doubts surfaced after a series of bizarre TV interviews, including one on CNN in which Falcon told his parents, "You said we did this for a show", when asked why he did not come down from the garage rafters during the search.

The family made the rounds on the morning talk shows yesterday and Falcon was sick during two separate interviews when asked why he hid.

Larimer county sheriff Jim Alderden admitted that Falcon's comments on CNN had clearly "raised everybody's level of scepticism" but investigators had no reason to believe the incident was a hoax.

Alderden said the family seemed genuine during the panic and he believed events could have unfolded just as they described: Falcon got frightened when his father scolded him for playing inside the balloon and hid in the garage out of fear.

The sheriff said his office had been flooded with calls and emails about the matter. He added that officials "have to operate on what we can prove as a fact and not what people want to be done".

The sheriff said that because of the "magnitude" of the balloon event, his office contacted social workers, but investigators asked them not to speak to the Heenes until the family had talked to authorities again.

Major Justin Smith of the sheriff's office said social workers were asked to get involved because of concerns about the family's storm-chasing. He said authorities wanted to make sure the children were in a healthy environment.

The sheriff was also asked about the sequence of events when the Heenes reported their child's disappearance to authorities.

The Heenes called the Federal Aviation Administration first, followed by a local TV station with a news helicopter, and then called the police. The sheriff said the TV station call made sense because the helicopter could have provided immediate assistance.

In the call to police, the boy's mother, Mayumi Heene, told a dispatcher in a panicked voice that her child was in "a flying saucer". She sobbed and said: "We've got to get my son."

It was not the first time someone from the Heenes' home had called police. A Colorado sheriff's deputy, responding to a hang-up in February at the home, heard a man yelling and noticed Mayumi Heene had a mark on her cheek and broken blood vessels in her left eye. She blamed a problem with her contact lenses.

Richard Heene said he had been yelling because his children were up past their bedtime. The husband and wife said nothing had happened and the deputy concluded he did not have probable cause to make an arrest.

If the balloon ordeal was a hoax, the parents could be charged with making a false report to authorities, a low-level misdemeanour, Alderden said.