KPMG Australia’s national chairman Martin Sheppard stepped down on June 23, along with two senior partners, marking the latest round of executive departures in what has become a full-blown crisis for the Big Four accounting firm.

The resignations come less than a month after CEO Andrew Yates and audit managing partner Julian McPherson left on May 29. In English: five of the firm’s most senior leaders have walked out the door in roughly 25 days.

How confidential documents sparked a firestorm

The scandal traces back to March 24, when Australian Senator Deborah O’Neill raised allegations in federal parliament that KPMG audit partners had improperly used confidential Lendlease board papers. The purpose, according to the claims, was to help secure audit contracts with major firms Westpac and Dexus.

The Westpac contract alone was reportedly worth $32 million. Using one client’s confidential materials to win business from another is, to put it mildly, not how audit independence is supposed to work.