More cyclists back claims of systematic doping by Lance Armstrong

More cyclists have supported and detailed claims that seven times Tour de France winner Lance Armstrong and his former United States Postal Service team participated in systematic doping.

Federal prosecutors have intensified their criminal investigation of cyclist Armstrong since the end of the Tour de France last month, The New York Times reports.

In May, Armstrong's former teammate Floyd Landis shook the cycling world by publicly accusing Armstrong and other team members of using performance-enhancing drugs and blood transfusions to gain an unfair advantage.

Landis said that Armstrong had encouraged doping and that the team had sold its bikes to help finance an expensive doping program.

According to a cyclist, who has been interviewed and two others privy to the inquiry, detailed some of his own drug use, as well as the widespread cheating that he said went on as part of the Postal Service team - all of which he said was done with Armstrong's knowledge and encouragement, the paper reports.

The rider, who has never tested positive for performance-enhancing drugs or methods, asked that his name not be used because investigators advised him not to speak publicly about the information he provided.

He has not been called before the grand jury that has been convened in Los Angeles to investigate the case, it says.

Armstrong is considered one of the more remarkable athletes in American history, someone who dominated his sport and also had a compelling personal story, having beaten testicular cancer.

Jeff Novitzky, a special agent for the Food and Drug Administration, is in charge of the investigation and has been interviewing Armstrong's associates and former teammates.