Former teammate Floyd Landis, who was stripped of the 2006 Tour de France title for doping, alleges in one of the lawsuits that Armstrong defrauded the U.S. government by repeatedly denying he used performance-enhancing drugs. The False Claims Act lawsuit could require Armstrong to return substantial sponsorship fees and pay a hefty fine. The AP reported earlier Tuesday that Justice Department officials were likely to join the whistleblower lawsuit before a Thursday deadline.
Jim Litke reported from Chicago, Jim Vertuno from Austin, Texas. Stephen Wilson in London and John L. Mone in Dearborn, Mich., also contributed to this report.