Lance Armstrong faces a powerful new adversary -- the United States government.

The Justice Department notified a federal court Friday that it is joining one of his former racing teammates in suing him for using performance-enhancing drugs during the Tour de France.

The government signed on to a lawsuit filed two years ago by Floyd Landis, one of Armstrong's former Tour de France teammates who has already admitted cheating. Among its claims: Landis saw Armstrong store and then re-inject his own blood to boost his performance, and Armstrong twice gave Landis banned hormones before races.

The government’s legal theory in joining the lawsuit is that when Armstrong agreed to race for the U.S. Postal Service team a decade ago in the Tour de France, he defrauded the government, violating its strict ban on illegal drugs, all the while claiming he did not use them.

Though the government’s action presents a serious new legal threat to Armstrong, the Justice Department case is not foolproof: Legal experts say Armstrong could argue that his contract with the team owners never explicitly prohibited blood doping, and he could claim that he never signed any agreement directly with the Postal Service that banned the practice.

But if the government wins, Armstrong could face huge fines, because the Postal Service paid at least $30 million to sponsor his racing teams.

Armstrong's attorney, Robert Luskin, said in a statement Friday that the Postal Service had no losses deserving of compensation.

"Lance and his representatives worked constructively over these last weeks with federal lawyers to resolve this case fairly, but those talks failed because we disagree about whether the Postal Service was damaged," Luskin said. "The Postal's Services own studies show that the Service benefited tremendously from its sponsorship -- benefits totaling more than $100 million."

After denying for years that he cheated, Armstrong gave a general admission last month in an interview with Oprah Winfrey. 

"This issue of performance enhancers, to me, we're going to pump up our tires, put water in our bottles and, oh yeah, that, too, is going to happen. That was it," he said.

The cycling website Velo News reported this week that Travis Tygart, the CEO of the US Anti-Doping Agency, wrote to Attorney General Eric Holder last month, urging the government to join the Landis lawsuit.

A decision by the Justice Department to join the case “in order to get to the bottom (or top) of this massive fraud would also be viewed by the press and public as necessary and legitimate,” the letter said.

Slideshow: Lance Armstrong’s controversial career

Joel Saget / AFP - Getty Images

The cyclist's historic run of Tour de France championships made headlines, as did his fall from grace after being stripped of the titles in 2012.

Launch slideshow

This story was originally published on Fri Feb 22, 2013 11:58 AM EST

Stefano Rellandini / Reuters file

U.S. Postal Service Team rider Lance Armstrong of the United States, the first six-time winner of the Tour de France cycling classic, waves in 2004 as he cycles past a U.S. flag during the rider's parade on the Champs-Élysées in Paris.

Updated 3:45 p.m. ET: The document of evidence has been released. Read it here from NBC News in a PDF file. Additional documents, including the sworn statements of Armstrong's teammates, are here.

American cyclist Lance Armstrong's career was "fueled from start to finish by doping," according to a detailed report of evidence against the seven-time Tour de France winner released Wednesday by the U.S. Anti-Doping Agency. The release of the report came hours after the agency issued a statement alleging that Armstrong participated in “the most sophisticated, professionalized and successful doping program that sport has ever seen.” 

In what it called a “Reasoned Decision” that it intends to share with worldwide cycling authorities, the USADA said that Armstrong was not merely a participant in what it called "a fraudulent course of conduct that extended over a decade," but a leader of the cheating scheme.  It describes USPS team members testifying to widespread use during the Tour de France of the human growth factor known as EPO, as well as testosterone and a human blood product known as Actovegin.

The report says Armstrong's teammates testified under oath to him giving them the drugs, plotting how to evade drug tests, and finally trying to intimidate teammates from testifying against him.

Armstrong has repeatedly denied the allegations, blasting the process as "an unconstitutional witch hunt," and cycling authorities who backed Armstrong's legal fight to block the case have said they want to see the material before deciding whether to appeal the U.S. agency's sanctions to the world Court of Arbitration for Sport. The New York Times reported that Armstrong's legal team tried to preemptively discredit the report in a letter sent Tuesday to the antidoping agency’s lawyer, Bill Bock. Timothy J. Herman, one of Armstrong’s lawyers, called the case a farce. “USADA, the prosecutor, now pretends to issue its own ‘reasoned decision,’ even though there was no judge, no jury and no hearing,” Herman said in the letter. The Times said Armstrong, through his spokesman, said he would not comment on the report.

But the USADA report described the evidence that Armstrong engaged in doping dating back to his first Tour de France victory in 1999 as "overwhelming," stating: 

"Five of the eight riders on the 1999 Tour de France team other than Armstrong, i.e., George Hincapie, Frankie Andreu, Tyler Hamilton, Jonathan Vaughters, Christian Vande Velde, all have first hand evidence of Armstrong’s violations of sport antidoping rules, and all have admitted their own rule violations in 1999.  Several other witnesses, including Emma O’Reilly and Betsy Andreu, also have first hand evidence of Armstrong’s involvement in doping in 1999.   

"Finally, although additional corroboration is not necessary given the testimony of USADA’s witnesses, as described in Section V.B. below, the retesting of Lance Armstrong’s samples from the 1999 Tour and the clear finding of EPO in six of the samples provides  powerful corroborating evidence of Armstrong’s use of EPO.  With or without this corroborating evidence, however, the evidence demonstrates beyond any doubt that Lance Armstrong used EPO during the 1999 Tour de France.  No other conclusion is even plausible."

Referring to a public statement from Armstrong that the team set a goal to repeatedly win the Tour de France, the agency said, "The path he chose to pursue that goal ran far outside the rules. His goal led him to depend on EPO, testosterone and blood transfusions but also, more ruthlessly, to expect and to require that his teammates would likewise use drugs to support his goals if not their own. The evidence is overwhelming that Lance Armstrong did not just use performance enhancing drugs, he supplied them to his teammates. ... It was not enough that his teammates give maximum effort on the bike, he also required that they adhere to the doping program outlined for them or be replaced."

The report describes how the agency says Armstrong allegedly avoided testing positive for drugs. First, it said, he had fewer than 60 tests, not the 500 to 600 his lawyers have claimed. Second, the riders tried to use undetectable drugs and methods of taking the drugs. And sometimes they just hid from inspectors:

"The most conventional way that the U.S. Postal riders beat what little out of competition testing there was, was to simply use their wits to avoid the testers.  Tyler Hamilton summarized:  "We also had another time honored strategy for beating the testing – we hid.  At the time, the whereabouts programs of drug testing agencies were not very robust, the UCI did not even have an out of competition testing program.  If a tester did show up, you typically would not get a missed test even if you decided not to  answer the door.  In any case, there was no penalty until you had missed three  tests.  So, avoiding testing was just one more way we gamed the system.

"The first rule of EPO use was to inject intravenously, the second rule was to use the drug in the evening and the third rule “was to always try to hide from testers and . . . try not to get tested.” The riders were advised to not answer the door if a tester came after they had used. 

"If a rider became aware that another had recently used drugs and learned that the drug  testers were around they would warn their teammate.  An example of this was when George Hincapie was aware that Lance Armstrong had recently used testosterone and (George) Hincapie learned  that testers were at the hotel. Hincapie texted Armstrong who dropped out of the race to avoid beingtested. 

"Also, the team staff was good at being able to predict when riders would be tested and seemed to have inside information about the testing. 

"USADA has also learned that at least in the second quarter of 2010 Lance Armstrong was providing untimely and incomplete whereabouts information to USADA, thereby making it more difficult to locate him for out of competition testing."

The USADA's report "is in excess of 1,000 pages, and includes sworn testimony from 26 people, including 15 riders with knowledge of the US Postal Service Team (USPS Team) and its participants’ doping activities," the agency said in a news release earlier in the day.

 "The evidence also includes direct documentary evidence including financial payments, emails, scientific data and laboratory test results that further prove the use, possession and distribution of performance enhancing drugs by Lance Armstrong and confirm the disappointing truth about the deceptive activities of the USPS Team, a team that received tens of millions of American taxpayer dollars in funding," the agency said.

Teammates of Armstrong's who offered evidence included Frankie Andreu, Michael Barry, Tom Danielson, Tyler Hamilton, George Hincapie, Floyd Landis, Levi Leipheimer, Stephen Swart, Christian Vande Velde, Jonathan Vaughters and David Zabriskie, the agency said.

The U.S. Anti-Doping Agency in August ordered that Armstrong’s many cycling titles from his 14-year career be erased and banned him from cycling for life because of the doping allegations. The agency is required to submit its evidence to the International Cycling Union.

David Epstein, a senior writer with Sports Illustrated, told NBC News that the USADA report may turn the page for the sport of cycling.

“You would never say that something like this is good for the sport because now I think 20 of 21 riders who had podium finishes in Lance's Tour wins have now been directly linked to doping either in investigations (or) positive tests or their own admissions," he said. "… Everybody sort of realized you kind of had to tear an era down before you could start a new one.  And I think that's what USADA and the men who testified are hoping this is.”

The CEO of the anti-doping agency, Travis T. Tygart, issued this statement:

Today, we are sending the ‘Reasoned Decision’ in the Lance Armstrong case and supporting information to the Union Cycliste International (UCI), the World Anti-Doping Agency (WADA), and the World Triathlon Corporation (WTC). The evidence shows beyond any doubt that the US Postal Service Pro Cycling Team ran the most sophisticated, professionalized and successful doping program that sport has ever seen.

The evidence of the US Postal Service Pro Cycling Team-run scheme is overwhelming and is in excess of 1000 pages, and includes sworn testimony from 26 people, including 15 riders with knowledge of the US Postal Service Team (USPS Team) and its participants’ doping activities. The evidence also includes direct documentary evidence including financial payments, emails, scientific data and laboratory test results that further prove the use, possession and distribution of performance enhancing drugs by Lance Armstrong and confirm the disappointing truth about the deceptive activities of the USPS Team, a team that received tens of millions of American taxpayer dollars in funding.

Together these different categories of eyewitness, documentary, first-hand, scientific, direct and circumstantial evidence reveal conclusive and undeniable proof that brings to the light of day for the first time this systemic, sustained and highly professionalized team-run doping conspiracy. All of the material will be made available later this afternoon on the USADA website at www.usada.org.

The USPS Team doping conspiracy was professionally designed to groom and pressure athletes to use dangerous drugs, to evade detection, to ensure its secrecy and ultimately gain an unfair competitive advantage through superior doping practices. A program organized by individuals who thought they were above the rules and who still play a major and active role in sport today.

The evidence demonstrates that the ‘Code of Silence’ of performance enhancing drug use in the sport of cycling has been shattered, but there is more to do.  From day one, we always hoped this investigation would bring to a close this troubling chapter in cycling’s history and we hope the sport will use this tragedy to prevent it from ever happening again.

Of course, no one wants to be chained to the past forever, and I would call on the UCI to act on its own recent suggestion for a meaningful Truth and Reconciliation program.  While we appreciate the arguments that weigh in favor of and against such a program, we believe that allowing individuals like the riders mentioned today to come forward and acknowledge the truth about their past doping may be the only way to truly dismantle the remaining system that allowed this “EPO and Blood Doping Era” to flourish. Hopefully, the sport can unshackle itself from the past, and once and for all continue to move forward to a better future.

Our mission is to protect clean athletes by preserving the integrity of competition not only for today’s athletes but also the athletes of tomorrow.  We have heard from many athletes who have faced an unfair dilemma — dope, or don’t compete at the highest levels of the sport. Many of them abandoned their dreams and left sport because they refused to endanger their health and participate in doping. That is a tragic choice no athlete should have to make.

It took tremendous courage for the riders on the USPS Team and others to come forward and speak truthfully. It is not easy to admit your mistakes and accept your punishment. But that is what these riders have done for the good of the sport, and for the young riders who hope to one day reach their dreams without using dangerous drugs or methods.

These eleven (11) teammates of Lance Armstrong, in alphabetical order, are Frankie Andreu, Michael Barry, Tom Danielson, Tyler Hamilton, George Hincapie, Floyd Landis, Levi Leipheimer, Stephen Swart, Christian Vande Velde, Jonathan Vaughters and David Zabriskie.

The riders who participated in the USPS Team doping conspiracy and truthfully assisted have been courageous in making the choice to stop perpetuating the sporting fraud, and they have suffered greatly. In addition to the public revelations, the active riders have been suspended and disqualified appropriately in line with the rules. In some part, it would have been easier for them if it all would just go away; however, they love the sport, and they want to help young athletes have hope that they are not put in the position they were -- to face the reality that in order to climb to the heights of their sport they had to sink to the depths of dangerous cheating.

I have personally talked with and heard these athletes’ stories and firmly believe that, collectively, these athletes, if forgiven and embraced, have a chance to leave a legacy far greater for the good of the sport than anything they ever did on a bike.

Lance Armstrong was given the same opportunity to come forward and be part of the solution. He rejected it. 

Instead he exercised his legal right not to contest the evidence and knowingly accepted the imposition of a ban from recognized competition for life and disqualification of his competitive results from 1998 forward. The entire factual and legal basis on the outcome in his case and the other six active riders’ cases will be provided in the materials made available online later today. Two other members of the USPS Team, Dr. Michele Ferrari and Dr. Garcia del Moral, also received lifetime bans for perpetrating this doping conspiracy.

Three other members of the USPS Team have chosen to contest the charges and take their cases to arbitration: Johan Bruyneel, the team director; Dr. Pedro Celaya, a team doctor; and Jose “Pepe” Marti, the team trainer.  These three individuals will receive a full hearing before independent judges, where they will have the opportunity to present and confront the evidence, cross-examine witnesses and testify under oath in a public proceeding. 

From day one in this case, as in every potential case, the USADA Board of Directors and professional staff did the job we are mandated to do for clean athletes and the integrity of sport.  We focused solely on finding the truth without being influenced by celebrity or non-celebrity, threats, personal attacks or political pressure because that is what clean athletes deserve and demand.

Rich Gardella of NBC News contributed to this report.