In halting the trial, U.S. District Judge Reggie Walton said he was troubled that prosecutors played a video referencing testimony by the wife of a witness before a congressional committee that he had previously ruled inadmissible. Walton said the portion of the video shown to the jury was prejudicial and he granted a motion by Clemens' lawyers for a mistrial.
The videotaped testimony referred to the wife of Clemens' ex-New York Yankees teammate, former pitcher Andy Pettitte, who told the committee Clemens had admitted taking a performance-enhancing substance in 1999 or 2000.
Pettitte's wife backed up her husband's testimony in an affidavit, The Washington Post reported. Walton concluded presenting Laura Pettitte's statements to the jury was unfair to Clemens.
A hearing on a possible retrial is set for Sept. 2.