Lance Armstrong is being investigated for possible criminal charges in Spain, ABC News has learned.
Sources both in the United States and Spain said the investigation relates to Armstrong's doping activities, which were spelled out in a U.S. Anti Doping Agency report.
Spanish sources believe crimes may have been committed in Spain and they are currently investigating to decide if charges should be brought against Armstrong and Spanish associates who worked with him on the U.S. Postal Service cycling team, the sources told ABC News.
The investigation is ongoing in multiple regions of Spain -- Alicante, Valencia, Girona and Tenerife.
An attorney for Armstrong did not immediately respond to requests for comment.
Armstrong was a resident of Girona, Spain, for several years during his reign as the Tour de France champ.
Spanish law does not make it a crime for an athlete to use performance enhancing drugs for personal use. In certain cases, athletes can be fined and have their licenses suspended.
However, if investigators can prove "trafficking, distribution and commercialization of doping drugs," that is a criminal offense carrying as many as two years in prison and fines of as much as 400,000 euros.
The investigation is described as being in a "very active and sensitive" phase.
In 2004, Armstrong lived in Spain with the singer Sheryl Crow. Floyd Landis, Armstrong's former cycling teammate, has told ABC News that during that period he babysat Armstrong's "blood fridge" in Spain "to make sure the temperature remained constant" when Armstrong traveled out of town with Crow.
Spain is currently front and center on the world stage as it bids for the 2020 Olympics. The country has been seen as soft on sports doping in the past and has been working to change that image.
In an interview with a German television station, the director of Spain's anti-doping authority, Ana Munoz, said, "What I can tell you so far is that we are following up on the Armstrong case. Not only because we were involved in the investigation back then but also because we are really interested that every person, Spanish or not, who has committed a crime in our country be prosecuted."