In a stinging memo handed down Tuesday, U.S. District Judge Paul Diamond says that testimony before his court raises the possibility that Krasner and a top deputy may have pressured prosecutors to lie in court.
The claims stem from an effort by a man convicted of murder in 2009 to have his conviction overturned -- a process led by Krasner's office.
In his memo Tuesday, the judge barred Krasner from any further participation in that effort, calling his actions "troubling and potentially illegal."
The judge has now referred Krasner to the U.S. Attorney's Office for investigation.
"I have thus reluctantly concluded that Philadelphia's highest law enforcement official and one of his top assistants may have violated the law. In these circumstances, with the issuance of this Memorandum, I refer the DAO, Mr. Krasner, and Stiegler to this District's United States Attorney's Office for investigation and other appropriate action," Judge Diamond wrote.
In a statement, Krasner said, "I respectfully and vigorously disagree with the court's findings of fact and conclusions of law. I look forward to appealing to the higher court as soon as the law allows. This remains a pending matter, which limits for now my and my office's ability to respond in the media."
Stay with Action News as we continue to follow this developing story.