Court documents suggest Mrs Heene planned the hoax days earlier

The mother of a boy thought to have been swept away in a giant helium balloon has admitted the incident was a hoax, according to court documents.

Mayumi Heene apparently told officials she and her husband "knew all along" her son, aged six, was hiding at home.

The papers, which were made public in the United States, also suggest the parents had told their children to lie.

According to the affidavit, Mrs Heene said the plan was to make the Colorado family more marketable to the media.

Six-year-old Falcon's apparent disappearance prompted a major rescue operation as the silver balloon soared through the sky.

It also captivated international audiences as live television pictures followed its course.

Falcon was later found in the garage of his home.

Taste for stardom

The court document says the parents devised the hoax about two weeks earlier.

"She [Mrs Heene] and her husband had instructed their three children to lie to authorities as well as the media regarding this hoax," it continues.

The father, Richard Heene, continues to deny that the balloon emergency was faked.

His lawyer David Lane said he was waiting to see evidence in the case, adding: "allegations are cheap."

The BBC's Rajesh Mirchandani, in Los Angeles, says it is believed that the Heene family - who had already twice appeared in reality TV shows - constructed the elaborate ruse because they were keen on another bid at stardom.

Larimer County Sheriff Jim Alderden has said he will recommend charges including conspiracy, contributing to the delinquency of a minor and making a false report to authorities.

Some of the most serious charges each carry a maximum sentence of six years in prison and a $500,000 (£305,000) fine.