Three-time Tour de France champion Greg LeMond has been served with a grand jury subpoena as part of a federal investigation of possible fraud and doping charges against Lance Armstrong and his associates, according to the New York Daily News.

The newspaper reported Friday on its website that a grand jury in the U.S. District Court of the Central District of California issued the subpoena, which requests testimony and documents related to the four cycling teams Armstrong has led U.S. Postal Service, Discovery Channel, Astana and RadioShack. The letter also orders LeMond to appear at a federal courthouse in Los Angeles on July 30, according to the Daily News.

"We are overjoyed," LeMond's wife, Kathy, told the newspaper. "I hope the truth will come out."

The federal doping investigation was spurred by allegations made by American cyclist Floyd Landis in a series of e-mails sent to cycling and doping officials this spring. Landis, who was stripped of his 2006 Tour title for doping, said the use of banned substances was common on the US Postal team when he rode with seven-time Tour winner Armstrong.

Doug Miller, the lead prosecutor, refused to comment to The Associated Press.

Armstrong, who's currently 57th in the Tour, said Wednesday he had not been subpoenaed or contacted by lead investigator Jeff Novitzky, who uncovered the BALCO doping scandal.

"Like I said, as long as we have a legitimate and credible and fair investigation, we'll be happy to cooperate, but I'm not going to participate in any kind of witch hunt," Armstrong said.

He repeatedly has denied any involvement in doping and reiterated that position again.

"As long as I live I will deny that," he said. "There is absolutely no way I forced people, encouraged people, told people, helped people, facilitated ... Absolutely not. 100 percent."