The Justice Department (DOJ) will join a lawsuit against Lance Armstrong for using banned performance enhancing drugs in cycling competitions, the department announced.

The whistleblower lawsuit was originally filed by one of Armstrong’s former teammates, Floyd Landis, who has himself admitted to doping.

The U.S. Postal Service (USPS) was a primary sponsor of Armstrong’s cycling team, and the DOJ case will claim Armstrong defrauded the federal government of $30 million in USPS sponsorship payments by violating its ban on illegal drugs.

“Lance Armstrong and his cycling team took more than $30 million from the U.S. Postal Service based on their contractual promise to play fair and abide by the rules — including the rules against doping,” Ronald C. Machen Jr., U.S. Attorney for the District of Columbia, said in a statement. “The Postal Service has now seen its sponsorship unfairly associated with what has been described as ‘the most sophisticated, professionalized, and successful doping program that sport has ever seen.’ ”