The lawyer for a man accused of tricking media and emergency officials into thinking his son was trapped in a runaway balloon, says his client expects to be charged and is willing to co-operate with police.

Lawyer David Lane said on Monday he expects charges to be brought against Richard Heene today or tomorrow, as investigators probe emails that allegedly show him discussing the hoax two months ago.

"These folks are absolutely willing to turn themselves in, so I don't want to see a perp walk done for media consumption," Lane said on the "Today" show on NBC.

On Thursday, six-year-old Falcon Heene's parents called 911, claiming the boy was in the UFO-shaped balloon when it drifted away from the family's backyard.

When the balloon landed after an 80-kilometre flight, Falcon was nowhere to be found. He was discovered five hours later at home, hiding in the rafters of the family's garage.

Police have said that the stunt, which sent news media and rescue officials into a frenzy, was faked in order to gain publicity for a reality show.

Investigators in Fort Collins now say they want to interview an associate of Heene's after emails surfaced that show the two discussed a balloon hoax as part of a PR campaign for a show.

Denver man Robert Thomas, who sold his story to the website, offered email exchanges between them and said the show would feature Heene as a mad scientist carrying out various experiments.

The story was published with the headline "Exclusive: I Helped Richard Heene Plan a Balloon Hoax."

Thomas, 25, said the plan they discussed to generate publicity for the show did not involve any children, however.

CNN's Nicole Collins, speaking from outside the family's home on Monday, told CTV's Canada AM that police have made no arrests yet but charges are expected soon.

The parents, Heene and his wife Mayumi, are expected to face misdemeanor charges for filing a false police report, but could also face felony charges for conspiracy, contributing to the delinquency of a minor and attempting to influence a public servant.

"We understand all three of the children knew about (the hoax). They are six, eight and 10 years old." Collins said.

"They are not going to be facing any charges. They are quite young and it's clear to authorities the parents were the ones orchestrating this whole ordeal and the children will not face any charges or punishment."

However, she said child protection agencies are involved in the investigation, and it's possible the parents' custody rights could be in jeopardy.

"It isn't uncommon for parental rights to be terminated when a crime is committed and parents are in on it," Collins said.

Larimer County Sheriff Jim Alderden said authorities are also looking into a media outlet in their investigation.

"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 would not name the outlet, but said he was not talking about a news organization and said it was a show that blurs "the line between entertainment and news."

It has emerged that the Heene family has been involved in reality television shows in the past, and that the parents met at acting school.