The annual report of the Inspector-General of the Australian Defence Force contained details of the progress of the investigation led by Justice Paul Brereton, which has been going since May 2016.

In the 2018/2019 report tabled in Federal Parliament, it noted that the inquiry focus had shifted from away from evidence and information gathering, to the consideration of alleged incidents; consideration of cultural, psychological, operational and organisational factors; and report preparation and finalisation.

“However, further lines of inquiry have continued to emerge,” the report said.

So far 55 separate incidents or issues were under inquiry covering a range of alleged breaches of the Law of Armed Conflict.

The report said most of the incidents were around unlawful killings of non-combatants or who were no longer combatants, but also “cruel treatment” of such persons.

“The Inquiry is not focused on decisions made during the ‘heat of battle’,” the report states.

“Rather, its focus is the treatment of persons who were clearly non-combatants or who were no longer combatants.”

It said the inquiry was now approaching the final stages of evidence-taking.

The report noted how difficult the investigation had been because of its serious subject matter and the challenges of tracking “vague rumours” about the conduct of Special Forces soldiers through multiple witnesses and documentary records back to its source.

“It has also taken some years for members of the Special Forces Community … to develop sufficient confidence in the inquiry and the genuineness of Defence senior leadership’s desire to find out if the rumours are true, to be prepared to make disclosures to the Inquiry,” the report said.

“During the reporting period and even now, some witnesses are only just becoming willing to make disclosures.”