Can the authorities relied on documents from data breach in taking legal action?

Documents are obtained via a data breach, and thereafter posted in the public domain.

The Paradise Papers are a set of 13.4 million confidential electronic documents relating to offshore investments that were leaked to a German newspaper by a group of hackers. The newspaper shared them with the  International Consortium of Investigative Journalists and a network of more than 380 journalists. Some of the details were made public on 5 November 2017 and stories are still being released.

The documents originate from legal firm Appleby, the corporate services providers Estera and Asiaciti Trust, and business registries in 19 tax jurisdictions. They contain the names of more than 120,000 people and companies. Among those whose financial affairs mentioned separately are, AIG, Prince Charles, Queen Elizabeth, US Secretary of Commerce and Glencore.

Glencore plc is a British–Swiss multinational commodity trading and mining company which headquartered in Switzerland. As of 2015, it is ranked tenth in the Fortune Global 500 list of the world's largest companies.

Documents from the Paradise Papers investigation showed that Glencore planned to move tens of billions of dollars “out of the Australian tax net” through an offshore web. The Paradise Papers also showed that Glencore Australia participated in complex financial instruments known as “cross-currency interest rate swaps'.

Glencore, in a statement, said the above, known internally as 'Project Everest', were intended to simplify the company’s asset ownership and "did not improve Glencore’s tax position”.

However from the Paradise Papers that was released to the public, it revealed that Glencore had backdated documents in the case. Backdating documents could have saved the Swiss-based company billion of dollars.

The Australian Tax Office pursued Glencore as it targets such swaps as possible tax avoidance tools. Glencore in their defence relied on “legal privilege” to prevent the Australian Tax Office from accessing emails, bank records, PowerPoint presentations and other files from the 2017 Paradise Papers investigation. Typically, documents marked “privileged” to be disclosed in court.