Plaintiffs lawyers accusing the bankrupt securities firm MF Global of bilking customers out of $1.6 billion have expanded their civil suit with new claims against the auditing giant PricewaterhouseCoopers.

On Monday the plaintiffs filed a consolidated amended class action complaint in the Southern District, adding both PwC and the futures and derivates exchange company CME Group as defendants. Co-lead counsel for the plaintiffs at Berger & Montague and Entwistle & Cappucci claim PwC and CME didn’t do enough to detect wrongdoing by MF Global’s executives and protect customer funds before MF Global declared bankruptcy in October 2011.