A year ago, a federal judge in St. Louis issued a sealed order finding DuPont Co. “knowingly committed a fraud upon the court” in a high-profile patent dispute with Monsanto Co.

On Friday, the news emerged that the judge had unsealed his order, adding to the woes of DuPont, which already had been hit with a $1 billion verdict in the case in August. The suit pitted Winston & Strawn for Monsanto against Kirkland & Ellis and Boies Schiller & Flexner for DuPont.