KPMG Australia’s latest response to a growing whistleblower scandal has exposed a flawed internal investigation, after a summary of findings described to The Australian Financial Review said the firm punished partners for minor infractions and failed to interview key witnesses.

The findings have added at least two new examples to the questions around how KPMG handled allegations that confidential client data may have been misused. The summary, described to the Financial Review, suggests the firm’s own process may not have been built to get to the bottom of the claims.

The case matters today because the document handed to parliament is said to cover all of KPMG’s investigations, putting the full scope of the firm’s response under public scrutiny as the whistleblower scandal continues to widen. The allegations center on the misuse of confidential client data, a charge that goes to the heart of trust in one of the world’s biggest professional services firms.

KPMG has denied most of the allegations, and the latest update makes clear that the parliamentary material is meant to account for every one of its investigations. That leaves a sharp tension at the center of the story: a firm trying to show it has dealt with the matter comprehensively, while fresh questions keep emerging about whether the people most able to explain what happened were ever heard.

For now, the strongest conclusion is that KPMG’s handling of the scandal has become part of the scandal itself. If the key witnesses were never interviewed, the firm will have to explain not just the allegations about client data, but why its own investigation appears to have missed the evidence that mattered most.