DENVER -- The Larimer County Sheriff indicated Saturday criminal charges will probably be filed against one or both of the parents of a 6-year-old boy who vanished into the rafters of his garage while the world thought he was zooming through the sky in a flying saucer-like helium balloon.

Sheriff Jim Alderden told reporters the likely charges are misdemeanors and no one in the family will be arrested. He said the sheriff's department will consult with the Federal Aviation Administration and other federal agencies regarding potential federal charges.

After the boy's parents, Richard and Mayumi Heene, met with sheriff's officials for much of the afternoon, Alderden didn't say who would be charged or what the charges would be, but he did say the parents spoke to investigators voluntarily and weren't under arrest.

Alderden previously said that if the balloon ordeal was a hoax, the parents could be charged with making a false report to authorities, a low-level misdemeanor.

"The Sheriff's Office is now in the process of obtaining a search warrant for their residence and we anticipate that there will likely be criminal charges filed at some time," said Eloise B. Campanell of the Larimer County Sheriff's Office.

"We were looking at Class 3 misdemeanor, which hardly seems serious enough given the circumstances," Alderden said Saturday. "We are talking to the district attorney, federal officials to see if perhaps there aren't additional federal charges that are appropriate in this circumstance."

He said there would be more information at a news conference Sunday.

The Heenes were expected to speak to reporters outside their home later Saturday, after a strange day that began with Richard Heene knocking on the windows of journalists camped outside his home and promising a "big announcement." A few hours later, he did an about-face when he told reporters that they should leave questions in a cardboard box on the front doorstep.

As Heene walked away, a reporter shouted, "Can you tell us once and for all if this is a hoax?"

"Absolutely no hoax. I want your questions in the box," Heene said, waving a cardboard container before going back into his home.

A circus-like atmosphere formed outside, including men holding signs and occasionally yelling "balloon boy." One sign read, "Put balloon boy on TV: America's Most Wanted."

Other gawkers carried aluminum-foil stovetop popcorn makers that resembled the silvery balloon launched from the family's backyard Thursday, with Falcon believed to be onboard.

While Richard and Mayumi Heene were at the sheriff's office, the couple's three sons remained home, apparently being watched by sheriff's officials. Authorities wouldn't comment on what was happening.

Alderden had said that he wanted to re-interview the family after Falcon told CNN that "you said we did this for a show" when asked why he didn't come out of his hiding place. Then Falcon got sick during two separate TV interviews when asked why he hid.

The balloon was supposed to be tethered to the ground when it lifted off, and no one was supposed to be aboard. A video of the launch shows the family counting down in unison, "3, 2, 1," before Richard Heene pulls a cord, setting the balloon into the air.

"Whoa!" one of the boys exclaims. Then his father says in disbelief, "Oh, my God!" He then says to someone, "You didn't put the (expletive) tether down!" and he kicks the wood frame that had held the balloon.

Falcon's brother said he saw him inside the compartment before it took off and that's why they thought he was in there when it launched. Heene said he had yelled at Falcon before the launch for getting inside.

Alderden said earlier that he thinks it's likely that Falcon ran off because he was scared of getting in trouble, later falling asleep in his hiding spot. He said he doubted that such a hyperactive boy could be ordered to stay quiet for the five hours he was missing.

Over the years, Richard Heene has worked as a storm chaser, a handyman and contractor, and an aspiring reality-TV star.

He and his family appeared on the ABC reality show "Wife Swap," and the show's producer said it had a show in development with the Heenes but the deal is now off. TLC also said Heene had pitched a reality show to the network months ago, but it passed on the offer.

Despite his attempts to get on TV, Heene insisted Saturday that he didn't know what kinds of questions were being asked about him because he didn't have cable.

"I'm going to place the box out front. Please write your questions down, because friends are telling me they're saying this and that. I have no idea what the news is saying," Heene said.