WASHINGTON - Roger Clemens must go to trial again to face perjury charges next April, a federal judge ruled Friday, saying a second trial would not violate the former baseball star's constitutional protection against double jeopardy.

In explaining his decision, U.S. District Judge Reggie Walton said the prosecutorial misconduct that forced a mistrial in July occurred too early in proceedings for him to conclude prosecutors were concerned about the jury or course of the trial. He also said that under current law he couldn't cite double jeopardy - the right of Americans not to face the same charges twice - to bar a new trial, even if prosecutors intentionally introduced evidence he had deemed inadmissible.

Defense attorney Mike Attanasio argued that prosecutors didn't deserve a new trial because they used a "win-at-all-costs strategy" by intentionally causing a mistrial. Assistant U.S. Attorney David Goodhand told the judge the improper evidence's introduction was a "regrettable" and "inadvertent" mistake that occurred in the "press of business."

Walton told prosecutors he had a hard time believing them because he had told them numerous times that the evidence was not admissible.

"I don't think there could have been any misunderstanding," Walton said. "It's hard for me to reach any other conclusion."

But ultimately, Walton said he didn't buy the defense's theory that federal prosecutors intentionally forced a mistrial - after hearing from just three witnesses - because they didn't like one of the alternate jurors.

Walton set jury selection for April 17 and left a gag order in place for members of both sides.

Walton's decision prolongs the legal ordeal for Clemens, 47, the seven-time Cy Young Award winner who played for the Astros from 2004 through 2006. It also gave the government another shot at a high-profile case that has taken public heat for its cost to taxpayers.

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Bill Miller, a spokesman for the U.S. Attorney's Office, declined to comment on Friday's proceedings. It wasn't immediately clear if Clemens' lawyers planned to appeal Walton's ruling.

The six counts of perjury against Clemens stemmed from his testimony during a U.S. House hearing in 2008 in which he denied using performance-enhancing drugs. Congress, which heard Clemens' former trainer Brian McNamee testify he injected Clemens with human growth hormone and steroids, referred the case to the Justice Department, which brought charges in August 2010.

Walton declared a mistrial on July 14, on day two of trial, because prosecutors played a video containing inadmissible evidence.

The video segment showed U.S. Rep. Elijah Cummings, D-Md., questioning Clemens about an affidavit from the wife of Andy Pettitte, Clemens' former teammate who was slated to testify in trial. Laura Pettitte swore that Andy had told her Clemens admitted to him that he used performance-enhancing drugs. Clemens famously responded that Andy had "misremembered" the conversation.

Assistant U.S. Attorney Steve Durham apologized to Clemens and to the court but denied trying to get around a judge's order.

"My reputation, my commitment to the honor of the job we do is far too important for me to engage in some type of end-run tactic, some type of clever tactic to get an advantage in a case," Durham told Walton. "We made a mistake. I made the mistake. It's on me."

Durham's comments were "spoken from the heart," defense attorney Attanasio responded. "But I have to say that that's not what we heard on July 14."

Walton also said he thought it was "unfair to require that Mr. Clemens has to pay over again for another trial," but he added he didn't know if he could make the U.S. government cover his legal expenses.

Kyle Glazier, Al Weaver and Amanda Russo of the Washington bureau contributed to this report.

puneet.kollipara@chron.com