WASHINGTON (CNN) -- Leading members of the House of Representatives asked the Justice Department on Wednesday to probe whether baseball great Roger Clemens "committed perjury and made knowingly false statements" during a congressional hearing.
Reps. Henry Waxman and Tom Davis sent U.S. Attorney General Michael Mukasey a letter saying Clemens' sworn testimony -- in a deposition and at a hearing -- on his use of steroids and performance-enhancing drugs as a player, "warrants further investigation."
Waxman is chairman of the House Committee on Oversight and Government Reform, and Davis is the panel's ranking member.
The lawmakers wrote that they "are not in a position to reach a definitive judgment as to whether Mr. Clemens lied to the committee."
"Our only conclusion is that significant questions have been raised about Mr. Clemens' truthfulness and that further investigation by the Department of Justice is warranted."
The Justice Department said it is reviewing the letter and had no further comment at this time.
Meanwhile, Clemens' attorney called the committee's decision "unwarranted and not supported by the facts."
"Roger will continue to fight these false allegations with every ounce of strength he has," said Rusty Hardin.
In his February 5 deposition and at the hearing eight days later, Clemens said that "he never used anabolic steroids or human growth hormone," the letter said. 
Watch Clemens deny steroid use »
"That testimony is directly contradicted by the sworn testimony of Brian McNamee, who testified that he personally injected Mr. Clemens with anabolic steroids and human growth hormone.
"Mr. Clemens' testimony is also contradicted by the sworn deposition testimony and affidavit submitted to the committee by Andrew Pettitte, a former teammate of Mr. Clemens, whose testimony and affidavit reported that Mr. Clemens had admitted to him in 1999 or 2000 that he had taken human growth hormone," the letter said.
Clemens and McNamee sat two seats apart at the hearing and told different stories under oath. In his five hours before the committee, Clemens told lawmakers that he received only vitamin shots from McNamee, his trainer until 2007.
McNamee told investigators in a Major League Baseball probe into steroid use that he injected the seven-time Cy Young Award winner with steroids, testosterone or human growth hormone on 16 occasions. He told the committee he saved physical evidence, including gauze pads and syringes, that would back up his account.
"I told the investigators that I injected three people, two of whom, I believe, confirm my account. The third is sitting at this table," he said.
McNamee said he never injected the pitcher with vitamins.
In a sworn statement, Pettitte told the committee that his New York Yankees teammate admitted using human growth hormone during a conversation in 1999 or 2000 -- a statement Clemens said his friend "misheard." Pettitte has admitted using growth hormone twice -- in 2002 and 2004.
"My problem with what Andy says and why I think he misremembers," Clemens testified, "is that if Andy Pettitte knew that I had used HGH, or I had told Andy Pettitte that I had used HGH before he would use the HGH, what have you, he would have come to me and asked me about it.
"That's how close our relationship was. And then when he did use it, I'm sure he would have told me that he used it."
At the hearing, Waxman said, "Someone isn't telling the truth."
McNamee's attorney, Mark Paoletta, said the House committee's probe and its referral to the Justice Department "go a long way toward showing all of us that no one is above the law -- not even our most revered athletes." E-mail to a friend 
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