WASHINGTON — Roger Clemens spent yesterday going door-to-door on Capitol Hill, lobbying congressmen investigating whether he used drugs. His accuser, Brian McNamee, gave a seven-hour deposition behind closed doors, and the trainer’s lawyers presented photographs of evidence they said prove the star pitcher was injected with steroids.

McNamee headed straight for an exit, not speaking a word to reporters, when he emerged from his interview with lawyers from the House Committee on Oversight and Government Reform. His attorneys wouldn’t discuss the deposition, but they did talk at length about two color photographs they showed the committee for the first time.

“Roger Clemens has put himself in a position where his legacy as the greatest pitcher in baseball will depend less on his ERA and more on his DNA,” said one of McNamee’s lawyers, Earl Ward.

The seven-time Cy Young Award winner’s repeated denials of McNamee’s allegations in the Mitchell Report about drug use drew Congress’ attention. Clemens spoke under oath to the committee Tuesday — the first time he addressed the allegations under oath, and therefore the first time he put himself at legal risk if he were to make false statements.

There is a public hearing scheduled for Wednesday, when Clemens, McNamee, and other witnesses, including Yankees pitcher Andy Pettitte, are to testify.

McNamee’s attorneys said their client turned over physical evidence to a federal prosecutor for the Northern District of California last month, shortly after Clemens held a January 7 nationally televised news conference at which he played a taped conversation between the two men with conflicting accounts at the center of the issue.

“At that point,” Ward said, “(McNamee) decided there was no holds barred.”

One photo shows a crushed beer can that Richard Emery, another of McNamee’s attorneys, said was taken out of a trash can in Clemens’s New York apartment in 2001. Emery said the can contained needles used to inject Clemens. That picture also shows what Emery said was gauze used to wipe blood off Clemens after a shot.

The other picture shows vials of what Emery said were testosterone, and needles — items the attorney said Clemens gave to McNamee for safekeeping at the end of the 2002 baseball season.

“We invite Roger Clemens to provide his DNA to the federal government,” Ward said, “so a determination can be made whether or not the times we say were taken from him are, in fact, his DNA.”

Asked about that, Rusty Hardin, one of Clemens’s attorneys, said the pitcher would comply with any request of that type from a federal authority.