The U.S. Court of Appeals for the Ninth Circuit has tapped Boies Schiller Flexner partner Christopher Caldwell as a special prosecutor to defend the contempt of court conviction of former Maricopa County Sheriff Joe Arpaio.

Caldwell was a founding partner in Los Angeles-based litigation boutique Caldwell Leslie & Proctor, which was absorbed by Boies Schiller last year. According to his firm bio, Caldwell served as a trial lawyer in the public integrity section of the Department of Justice’s Criminal Division in the mid-1980s before moving into private practice where he focuses on cases involving the entertainment industry, intellectual property, securities, employment, professional liability, and white-collar crimes. Caldwell didn’t immediately respond to an email seeking comment.