Richard and Mayumi Heene may have to repay search costs

The US parents accused of staging a hoax by claiming their six-year-old son was adrift in a helium balloon have pleaded guilty to charges in the case.

Richard Heene pleaded guilty to a felony charge of attempting to influence a public servant.

His wife, Mayumi Heene, pleaded guilty to a misdemeanour charge of false reporting during the search for the missing child.

The couple face the possibility of prison time and probation.

Hiding at home

The lawyer for the pair, David Lane, says the pleas are part of an agreement with officials to avoid the possible deportation of Mayumi Heene, who is a Japanese citizen.

The judge told the Heenes they could also have to pay back some of the cost of the rescue attempt, which had National Guard helicopters chasing the balloon.

"There are financial consequences that could be significant," District Judge Stephen Schapanski said.

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Mr Lane earlier in the week said prosecutors had agreed to recommend sentences of probation with the possibility of up to 60 days in jail for the wife and 90 for the husband.

Sentencing is expected on 23 December.

The incident in Colorado led to a media storm.

The couple reported that their young son had been carried away by a helium balloon - whose progress was then tracked by news organisations.

Police carried out an intensive search for the boy after the balloon landed about 64km (40 miles) north of Denver and was found to be empty.

But it then transpired that the child was hiding at home and days later the couple were accused of an elaborate hoax.