Lance Armstrong is being accused by at least three ex-teammates of using performance enhancing drugs - a charge Armstrong has always vehemently denied.
The accusations, CBS News Chief Investigative Correspondent Armen Keteyian said on "The Early Show on Saturday Morning," were uncovered in a six-month "60 Minutes" investigation that's reported by correspondent Scott Pelley in a piece airing Sunday night.
So far, Armstrong has specifically denied the charges made by one of the three ex-teammates, Tyler Hamilton, who admitted he also took PEDs.
Excerpts from the interview, which will be featured on Sunday's broadcast, were released Thursday. On Friday, Hamilton surrendered the gold medal he won in the 2004 Olympics.
On Armstrong's publicist's website, facts4lance.com, Armstrong's attorney, Mark Fabiani, tears into Hamilton, calling him "a confessed liar in search of a book deal."
Fabiani also says, "Every cyclist who appeared on '60 Minutes' has in the past sworn that they never doped. Now, their stories have suddenly changed out of desire for money and the need for attention. Just as eager for money and attention, '60 Minutes' has embraced these falsehoods uncritically and enthusiastically. But greed and a hunger for publicity cannot change the facts: Lance Armstrong is the most tested athlete in the history of sports: He has passed nearly 500 tests over twenty years of competition. The time has long passed for this nonsensical investigation to stop, and for the enormous wasted resources to be re-directed to investigations that might actually protect Americans from wrongdoing."
Nonetheless, Keteyian said on "Saturday Morning," Armstrong "is in the biggest mess of his life."
"True to form," Keteyian said Saturday, "when threatened by rival riders or, as now, damning doping accusations, Lance Armstrong went on the offensive."
One of the "most startling new claims" of the "60 Minutes" piece, Keteyian says, is that the three ex-teammates of Armstrong's have provided sworn testimony to a federal grand jury in Los Angeles that they witnessed the seven-time Tour de France champion taking performance-enhancing drugs.
"It appears," Pelley says in his report, "the federal investigation, with its subpoenas and sworn grand just testimony, has broken cycling's code of silence.
"We don't know how many U.S. Postal riders were using performance-enhancing drugs, but we have learned that at least three have told federal authorities they used banned substances and witnessed Armstrong using them, too.
"One of those riders is Armstrong's other close teammate, George Hincapie. We're told that now, for the first time, Hincapie has testified to federal investigators that he and Armstrong supplied each other with the blood-booster EPO and discussed having used testosterone, another banned substance, during their preparation for races.
"Through his attorney, Hincapie declined to be interviewed, citing the ongoing investigation."
"When it comes to such an investigation," Keteyian observed Saturday, "sworn testimony from Hincapie is a game-changer. Quiet, untouched by scandal, he is the only rider to be at Armstrong's side for all seven of his record Tour de France victories. If anyone would know if Armstrong was doping, it would be Hincapie."
The "60 Minutes" piece also refers Armstrong's former U.S. Postal teammate Frankie Andreu.
On "Saturday Morning," Keteyian added, "For all Lance Armstrong's charges that the people who are accusing him of illegal doping are not credible, no word yet from team Armstrong about Hincapie's very damaging grand jury testimony."
"The response from Armstrong's team to the ('60 Minutes') piece has been pretty aggressive, right?" Russ Mitchell, "Early Show on Saturday Morning" co-anchor, asked Keteyian.
"Absolutely," Keteyian replied."Their default position, time after time after time, whether you're a book author, a magazine writer, a mechanic, a masseuse, has been to attack the credibility of the people making the accusations. I don't know everything in the '60 Minutes' piece, but I know a lot of it. And this is by far the most detailed and, I think, the most damaging piece that's been done."
Hincapie, Keteyian told Mitchell is, "for lack of a better term, kind of the Rosetta stone here. He's the game-changer. George is the only rider to ever race with Lance side-by-side on all seven of his Tour de France victories. He's untouched by scandal. He's very quiet. Unassuming. But he knows -- if anybody knows, it's George."
The grand jury proceedings, Keteyian added, "could wrap up as early as next month. But I'm having a hard time, as (are) a lot of other people, trying to figure out what the government is really trying to accomplish here.
"Lance last raced in 2005 in the Tour. He's been retired for a number of years now. And they're not even going to get him on doping charges. It's gonna be something to do with defrauding his sponsors for things that happened in another country. So, it's gonna be very interesting, if there is an indictment, and that's a big if, just where this goes."