The presiding judge in Roger Clemens’s trial on perjury charges called an abrupt end to the proceedings on Thursday by declaring a mistrial. U.S. District Judge Reggie B. Walton ruled the prosecution had introduced inadmissible evidence involving Andy Pettite, Clemens’s former teammate and a witness for the prosecution. Clemens’s lawyer requested the mistrial ruling after Assistant U.S. Attorney Steven Durham brought up a statement from Laura Pettite, Andy Pettite’s wife, which violated a pre-trial ordering barring references to her testimony, unless in rebuttal. Prosecutors allege Clemens told Pettite he used human growth hormone (HGH), a conversation Pettite subsequently reported to his wife. Clemens’s trial is in connection to testimony the former star pitcher gave before Congress, during which he said he’d never used performance enhancing drugs such as HGH. Walton has called for a September 2 hearing to determine whether to hold a new trial.