As federal authorities seek to extradite a deep-sea treasure hunter arrested last week after more than two years as a fugitive, his former business associates want to know what happened to millions of dollars' worth of gold he recovered from a historic shipwreck.

Tommy Thompson is scheduled for an extradition hearing Wednesday in a federal court in Florida. He's being held on an arrest warrant filed after he failed to appear in an Ohio courtroom to explain what happened to all the gold he recovered from a 19th-century shipwreck off the South Carolina coast.

U.S. marshals arrested Thompson and his longtime assistant in a Boca Raton hotel on Jan. 27. Authorities believe the two had been staying in a suite there for up to two years, paying with cash, using fake names and keeping a low profile.

Less than 48 hours after the arrests, investors and sonar analysts who sued Thompson about a decade ago for their share of the treasure filed subpoenas in federal court, seeking any documents from the hotel that may show how Thompson has been living a cash-only lifestyle for so long.

"If he has millions of dollars of cash hidden somewhere, if he has 500 gold coins hidden somewhere, those are assets he needs to answer questions about," said Mike Szolosi, a Columbus, Ohio attorney representing nine sonar analysts who sued Thompson in 2006, arguing that they'd been cheated out of 2 percent of profits from gold recovered from the shipwreck, plus years of interest.

That lawsuit is still pending, as is another filed by an Ohio newspaper company that never saw returns after investing about $1 million to help fund Thompson's dream to find the ship.

Thompson, now 62, made history in 1988 when he found the S.S. Central America, known as the Ship of Gold, which sank in a hurricane about 200 miles off the South Carolina coast in September 1857, claiming 425 lives. Thousands of pounds of California gold went down with the vessel -- so much gold that it contributed to an economic panic.

Much of the gold that Thompson recovered was sold to a gold marketing group in 2000 for about $50 million. Thompson's attorneys and supporters have said the treasure hunter didn't steal anything, and that most of the sale proceeds went toward repaying loans and legal fees spanning decades.

Szolosi said there's ample evidence that Thompson has 500 commemorative coins made from gold bars recovered from the shipwreck and worth at least an estimated $2 million.

Thompson will have to go through the extradition process in Florida before he's brought to Ohio, where he will have to answer to the criminal arrest warrant in federal court, and eventually, to the two lawsuits by the investor and sonar analysts.

During a brief court hearing last week, a shackled and bearded Thompson suggested he would fight extradition to Ohio, where he grew up and was based before he moved to Florida in the mid-2000s.

Thompson told U.S. Magistrate Dave Lee Brannon he has "been very ill for a number of years" with a type of encephalitis, an overactive immune system and allergies that would be exacerbated if he is taken north.

The last time Thompson was seen before his arrest was in 2012 at a mansion in Vero Beach, Florida, that he had rented since 2006. He paid the monthly $3,000 rent with cash and put the utilities in the landlord's name.

There, authorities say they found a book called "How to Live Your Life Invisible" describing how to get by on a cash-only basis. They also found bank wraps for $10,000; metal pipes that authorities believed were used to store money underground; and 12 active cellphones, each used for specific attorneys or family members.