The Australian Defence Force has asked federal police to investigate a threatening letter sent to a member of the SAS.
Defence says the threatening letter related to the soldier giving evidence to an inquiry into the conduct of Australian forces in Afghanistan.
It says it is a crime to make such a threat.
The Inspector General of the Australian Defence Force (IGADF) is conducting a secretive and sweeping inquiry into Australia’s elite troops, including possible breaches of the Geneva Convention.
The inquiry, which has been running since May 2016, is headed by New South Wales Supreme Court Judge and Army Reserve Major General Paul Brereton.
It has been examining claims of illegal actions committed by members of the Special Air Services Regiment and commando units during the 12-year conflict.
The letter was mailed to the special forces soldier, but the names of witnesses to the inquiry are not revealed and hearings are conducted in private.
Defence points out that witnesses are protected by law from intimidation and from liability for what they tell the inquiry.
The Inspector-General has also been also advertising in local newspapers in Afghanistan for people to come forward.
The Inspector-General’s report is expected to be released by the end of this year.
The ABC reported earlier this week that the two-year long investigation has uncovered numerous concerns about the conduct of Australian special forces in Afghanistan, including several incidents of possible unlawful killings.
Several high-level sources in the Defence community have confirmed to the ABC that Justice Brereton is nearing the end of his work and is soon expected to highlight a handful of cases where suspected homicide could be referred for further investigation.
It is not known what incidents the concerns relate to, but sources have told the ABC that five cases involving alleged unlawful killings have been uncovered.