Former major league trainer Brian McNamee and pitching great Roger Clemens testified before the U.S. House of Representatives Committee on Oversight and Government Reform. Committee Chairman Rep. Harry Waxman, D-Calif., said the hearing focused on the accuracy of information McNamee provided former Sen. George Mitchell, D-Maine, in his investigation about the use of steroids and other performance-enhancing drugs in baseball.

Clemens said he never used steroids, human growth hormone or other performance-enhancing drugs.

Burton challenged McNamee about statements he made in which he denied knowledge, use and distribution of steroids and human growth hormones.

"Is that a lie," Burton asked several times.

"Yes," McNamee responded.

"You're here as a sworn witness," Burton said. "You're here ... after telling lie after lie after lie after lie. ... I don't know what to believe. ... I know one thing I don't believe and that's you."

If it is found that Clemens used performance-enhancing drugs, then he should be held accountable, Burton said.

"But I don't see any evidence of Mr. Clemens wrong-doing so far," Burton said.