WASHINGTON — A federal grand jury is investigating whether Roger Clemens lied to Congress last year, two people briefed on the matter told The Associated Press on Monday.

Both spoke on condition of anonymity because grand jury proceedings are supposed to be secret.

Congress asked the Justice Department to look into whether the seven-time Cy Young Award winner lied last February when he testified under oath at a deposition and a public House hearing that he never took illegal performance-enhancing drugs.

That contradicted the sworn testimony of his former personal trainer Brian McNamee, who said under oath that he injected Clemens with steroids and human growth hormone.

By bringing the case to a grand jury, the Justice Department escalated the case from an FBI investigation. A grand jury allows prosecutors to get sworn testimony from witnesses and collect documents.

The grand jury's involvement first was reported by ESPN.com.

McNamee's lawyer, Richard Emery, said Monday his client has not been called as a grand jury witness or received a subpoena. But he does expect McNamee to testify again.

"We will be cooperating. We've been in contact with the federal authorities for a year and a half," Emery said. "We look forward to the results, which we fully expect will show that Brian has been telling the truth all along."

In the Mitchell Report on doping in baseball, McNamee said he injected Clemens more than a dozen times with steroids and HGH from 1998-01. Clemens' repeated denials of those accusations drew Congress' attention — and the former pitcher then made more denials under oath.

Shaun Kelley, owner of a Houston training center, said he had taken a polygraph test for FBI investigators John Longmire and Heather Young last April and that he had denied meeting Clemens or providing the pitcher or any of the pitcher's associates with illegal substances. Kelley said he employed Clemens' stepsister Bonnie Owens for about a year.

Kelley said neither he nor his lawyers had been contacted by the grand jury.

"It is just not fair for me, because they just come down here and throw me under the bus, and I lose half-a-million of business," Kelly said Monday in a telephone interview.

"I know in my heart I passed it," he said of the polygraph, "but the FBI is not known for admitting their mistakes."

Rusty Hardin, a lawyer for Clemens, could not immediately be reached for comment. Rep. Henry Waxman, the California Democrat who chaired the House committee that heard the testimony of Clemens and McNamee last year, declined to comment.