“A few days ago, the U.S. federal government officially asked the French judicial authorities to co-operate in the investigation,” the source, who spoke on condition of anonymity, told Reuters.
The source added that a meeting between Food and Drugs Administration (FDA) special investigator Jeff Novitzky, U.S. federal prosecutor Doug Miller, U.S. Anti-Doping Agency CEO Travis Tygart and French Anti-Doping officials took place in France.
The American trio also met with members of Interpol in Lyon.
French sports daily L’Equipe reported in 2005 that samples from Armstrong from the 1999 Tour showed traces of the banned blood-boosting EPO.
Armstrong, who has never tested positive, was cleared by an independent panel although then World Anti-Doping Agency (WADA) president Dick Pound questioned the integrity of the investigation.
Former French Anti-Doping Agency president Pierre Bordry, who resigned in September, had said he would hand over Armstrong’s samples should he get an official request from Novitzky.
Armstrong quit top-level competitive cycling in Europe after this year’s Tour de France.
Landis, the disgraced 2006 Tour winner and a former team mate of Armstrong, said in May that Armstrong used performance-enhancing drugs.
Landis was handed a two-year suspension and stripped of the Tour title after he tested positive for high levels of testosterone during the race.
