Lance Armstrong could face the prospect of jail time and the repayment of millions of dollars following his reported admission that he used performance-enhancing drugs during his cycling career, legal experts said.
And the fallout from his confession to American talk show host Oprah Winfrey could also threaten the sport that made him rich and an inspiration to millions of people, with a top Olympic official warning about the sport's future at the games.
Already banned for life and stripped of all his race wins, including his seven Tour de France victories, Armstrong's problems may only just be starting.
CBS Television reported on Tuesday that the disgraced rider had offered to pay more that $5 million (3.1 million pounds) to the U.S. government in compensation for an alleged fraud against the U.S. Postal Service, which for years sponsored his cycling team.
The network also said he offered to cooperate as a witness in a U.S. investigation but the Department of Justice turned down his request, raising the prospect that he could yet serve time in prison.
"Having previously testified under oath and denying the doping allegations, Armstrong's admissions would make perjury or obstruction of justice charges a relatively easy charge for prosecutors," said Andrew Stoltmann, a Chicago attorney.
The full extent of Armstrong's admission is yet to be revealed although U.S. media said on Monday he confessed to doping in an interview with Winfrey to be aired this week.
The talk show host confirmed the reports on Tuesday in an appearance on the "CBS This Morning" show.
"I'm sitting here now because it's already been confirmed," said Winfrey, who interviewed Armstrong for more than two and a half hours on Monday in a hotel in Austin, Texas.
It will not come as a great surprise that Armstrong's triumphant rides through the French Alps were fuelled by more than natural energy. The mountain of evidence against him was already overwhelming and the pressure to confess was building.
From the moment it was announced last week he had agreed to the interview with Winfrey, it was widely expected the 41-year-old cancer survivor would make some sort of confession but even Winfrey was surprised by what he said.
"He did not come clean in the manner that I expected," she said, without elaborating on the specifics.
"For myself, my team, all of us in the room, we were mesmerized and riveted by some of his answers.
"I didn't get all the questions asked, but I think the most important questions and the answers that people around the world have been waiting to hear were answered."
Armstrong's world began to crumble in October last year when the U.S. Anti-Doping Agency released a detailed report with sworn testimony from dozens of people that described him as the ringmaster of the "most sophisticated, professionalized and successful doping program that sport has ever seen."
Armstrong had always denied the accusations made against him, which involved the use of anabolic steroids, human growth hormone, blood transfusions and other doping.
If a damning confession emerges, Armstrong could face a range of legal challenges. A British newspaper is suing him to recover about $500,000 it paid him to settle a libel lawsuit and he could be forced to pay back amounts including $7.5 million to SCA Promotions, a Dallas-based company that paid him a bonus for his Tour de France wins.
His former teammate, Floyd Landis, a self-confessed cheat, filed a lawsuit against him for defrauding the U.S. government, while his sponsors, which have deserted him in droves, could also have a case for compensation, according to lawyers.
"Without knowing the details of the interview, it is difficult to read the tea leaves regarding the implications of his admissions," said Matthew Rosengart, a former federal prosecutor. "But it is reasonable to assume that the exposure would likely fall within the civil rather than in the criminal arena."
According to some of the leaked reports from the interview, Armstrong offered to testify against others involved in doping. That could open up the possibility of a reduction in his punishment if he owned up to the World Anti-Doping Agency (WADA).
"Only when Mr. Armstrong makes a full confession under oath - and tells the anti-doping authorities all he knows about doping activities - can any legal and proper process for him to seek any reopening or reconsideration of his lifetime ban commence," WADA Director General David Howman said in a statement.
Cycling, one of the showcase sports at the Olympics, could be hurt. International Olympic Committee (IOC) member Dick Pound told Reuters the sport could be kicked out of the Games if officials were implicated in a cover-up.
"We could say, 'look, you've clearly got a problem. Why don't we give you four years, eight years to sort it out?'" Pound said.
"And when you think you're ready come on back we'll see whether it would be a good idea to put you back on the program."
The International Cycling Union (UCI) has already acknowledged it received a $100,000 donation from Armstrong in 2002 but denied the money was part of covering up a positive drug test.
The UCI recently set up an independent commission to investigate the case and wants Armstrong to testify under oath.
"The UCI notes the media speculation surrounding the interview and reports that he has finally come clean and admitted doping during his cycling career," the union said.
"If these reports are true, we would strongly urge Lance Armstrong to testify to the independent commission established to investigate the allegations made against the UCI in the recent USADA reasoned decision."
Armstrong's interview with Winfrey will be broadcast over two nights - at 9:30 p.m. EST on Thursday (0230 GMT on Friday) and 9 p.m. EST on Friday