The judge in the Roger Clemens federal perjury trial abruptly declared a mistrial on the second day of testimony after the government inadvertently allowed the jury to hear statements from a U.S. congressman discussing the credibility of one of the key witnesses against the former All-Star baseball pitcher.

Here’s the press release from the AP:

The judge has declared a mistrial in the Roger Clemens perjury case, the Associated Press reports.U.S. District Judge Reggie Walton in Washington said Clemens could not be assured a fair trial after prosecutors showed jurors evidence against his orders in the second day of testimony.Walton scheduled a Sept. 2 hearing to determine whether to hold a new trial.Clemens is accused of perjury in denying to a Congressional committee that he had used steroids. Update at 12:07 p.m. ET: NBC Justice correspondent Pete Williams says the evidence involved testimony before Congress by the wife of former Clemens teammate Andy Pettitte. But the judge had ruled that the material could not be included because it involved hearsay evidence.

When the prosecution showed a video of a member of Congress reading portions of her testimony, the judge stopped the proceedings, Williams reports. That, in turn, led to the mistrial declaration.

Update at 12:01 PM:

Prosecutors suggested the problem could be fixed with an instruction to the jury to disregard the evidence, but Walton seemed skeptical.

He said he could never know what impact the evidence would have during the jury’s deliberations “when we’ve got a man’s liberty at interest.”

I’m not going to make any comments except to say you must expect the unexpected when Roger Clemens is involved. Who knows what really happened here?