Federal prosecutors on Thursday asked a judge in Miami to halt proceedings in a $260 million legal malpractice lawsuit against Los Angeles-based Mitchell Silberberg & Knupp and one of its its partners, David Gordon, asserting that the case could interfere with an ongoing grand jury investigation.

In a nine-page federal district court filing, the government said the previously undisclosed investigation is separate from an ongoing criminal prosecution of three of Gordon and his firm’s former clients: Ariel Quiros, William Stenger and William Kelly. The trio face fraud charges for allegedly operating a Ponzi scheme through their network of businesses, which included the ski resort company Jay Peak, Inc.