A federal judge says a one-time billionaire real estate mogul who's languished for six months in a Montana jail faces a "final opportunity" to come clean about a Mexican property sale during a trial that starts Monday.

NBC Montana reports U.S. District Judge Sam Haddon jailed 65-year-old Tim Blixseth in April for not providing a full accounting of what happened to $13.8 million from the sale of an oceanside resort in the Mexican state of Jalisco.

The 2011 sale violated a court order from another judge who oversaw the bankruptcy case of the Yellowstone Club, a private Montana ski area founded by Blixseth that caters to the ultra-wealthy.

Experts say that if Haddon remains unsatisfied following this week's trial, the judge could refer the matter for criminal prosecution.

Blixseth's attorneys say he's given a full accounting of the money.