The United States government has joined a multi-million dollar lawsuit against the disgraced cyclist Lance Armstrong.
The government is accusing Armstrong of defrauding the US Postal Service by taking its sponsorship money at the same time he was doping and using performance-enhancing drugs in violation of cycling rules.
The cyclist was stripped of his Tour de France titles and banned for life from cycling in 2012 after accusations he had cheated for years. In January, he said the accusations were true in an interview with television host Oprah Winfrey.
Armstrong and his teammates from Tailwind Sports wore the logo of the Postal Service during their record-breaking wins.
The government said the sponsorship money totalled more than $US30 million and the lawsuit is designed to help the Postal Servce recoup the money, Reuters reports.
Armstrong's lawyer said he plans to contest the suit because the Postal Service was not actually damaged and received benefits totaling more than $US100 million.
Prosecutors have said they do not expect to charge him with a crime.
The government is suing under the False Claims Act, an 1863 law that encourages private individuals to file suit when they have evidence of fraud involving government money.
When the government believes a suit has merit, it may take over the litigation. The individuals, or whistleblowers, get a portion of the proceeds if the case is successful.
Former Armstrong teammate Floyd Landis filed a sealed whistleblower suit against Armstrong in 2010. The decision by the government to join the suit triggered its unsealing.
Lawyers for Mr Landis did not respond to requests for comment.