U.S. District Judge Paul S. Diamond has referred Philadelphia District Attorney Larry Krasner and one of his top supervisors, Matthew Stiegler, to the U.S. Attorney's Office for investigation into potential criminal charges, including conspiracy or obstruction of justice. This referral stems from their handling of a case where a man is seeking to overturn his murder conviction. Judge Diamond also disqualified Krasner and Stiegler from participating in the underlying case, citing "troubling" and "disturbing" actions that he believes may be illegal.

The judge's decision was prompted by testimony from Krasner's staffers during hearings, which suggested that Krasner and Stiegler pressured other employees to protect Stiegler, urged them to lie in court, and threatened "consequences" for non-compliance with Krasner's orders. Diamond, a George W. Bush appointee, stated he "reluctantly concluded that Philadelphia’s highest law enforcement official and one of his top assistants may have violated the law." This move is considered rare but not unprecedented for a judge to refer potential wrongdoing to prosecutors.

The referral has created significant legal and political uncertainty for Krasner, a nationally recognized leader of the progressive prosecutor movement. He has denied wrongdoing and plans to appeal Diamond's ruling. While Republican opponents have called for his resignation, elected Democrats have largely remained silent, with some reportedly discussing contingency plans if Krasner is forced from office before his term ends in 2030. The investigation by the U.S. Attorney's Office is expected to be lengthy, potentially taking months or even years, and its outcome is difficult to predict.