When Braden Chapman, newly patrolling with Australian special forces in Afghanistan, saw a fellow soldier shoot dead an unarmed Afghan man whose arms were raised, "I was taken aback," he recalls, "because I knew it was an execution."

The alleged incident occurred in 2012, when Chapman was serving as an electronic warfare operator in Uruzgan province in southern Afghanistan. He tells NPR that another soldier tried to put "words into my mouth." He told Chapman to say that the Afghan man had been moving "to gain tactical advantage" on the Australian troops.

Chapman was serving in his first deployment. He recalls hearing casual talk from members of his elite squad about other killings the unit had committed in Afghanistan stretching back to 2005.

"I guess that's just how this unit operates," he recalls thinking.

It was, to some extent. That became evident on Thursday, when findings were made public of a four-year inquiry into suspected war crimes by Australia's special forces in Afghanistan, who numbered some 3,000 among a force of 26,000.

The Inspector-General of the Australian Defense Force Afghanistan Inquiry Report, as it is formally known, recommends that 19 former and current Australian soldiers be referred to criminal investigation for killing 39 Afghans in 23 separate incidents. Most of the killings occurred around 2012. The report also recommends disbanding a squadron within the Special Air Services Regiment, more widely known as Australia's SAS, its most elite forces. This was the squadron largely involved in the killings.

"Rules were broken, stories concocted, lies told and prisoners killed," said Gen. Angus Campbell in a speech broadcast live on Australian television as the report was released. "Those who wish to speak up were allegedly discouraged, intimidated and discredited."

Elite soldiers lied about killing unarmed men, including prisoners and farmers. They planted guns on some corpses to falsely claim they'd killed combatants.

Some were forced to kill Afghans as part of an initiation ritual.

"This shameful record includes alleged instances in which new patrol members were coerced to shoot a prisoner in order to achieve that soldier's first kill, in an appalling practice known as 'blooding,'" said Campbell.

Addressing the Afghan people, he said: "I sincerely and unreservedly apologize for any wrongdoing by Australian soldiers."

The Afghan government has acknowledged that Australian Prime Minister Scott Morrison called President Ashraf Ghani to inform him of the report.

"We are grateful for their support, but greatly disappointed in their misconducts and the war crimes they have committed. Apology and compensation to the victims' families won't be enough. Australian federal police should investigate the cases referred to them and serve justice," an Afghan official tells NPR. He did not want to be named since he was not authorized to give a statement before the Afghan government had officially responded.

The Australian inquiry was triggered in 2016, after Samantha Crompvoets, a military sociologist, compiled gruesome accounts of alleged atrocities while she was investigating the culture of Australia's special forces.

It evolved into the most wide-ranging military inquiry to date of any armed forces involved in the U.S.-led coalition in Afghanistan. Led by a Supreme Court judge and retired reservist, Maj. Gen. Paul Brereton, it examined the period from 2005 to 2016.

"Just looking at the post-2001 period, there have been very few efforts by any of the countries involved to really look into what has been a long history of very serious abuses by international forces," says Patricia Gossman, the associate Asia director for Human Rights Watch. "So if if Australia actually does what it should do, which is to pursue genuine criminal investigations and prosecutions, it would it be unprecedented and so important, not just for Australia... but for the Afghans who have never, ever seen justice for so many war crimes over a long period of this war."

The report has triggered calls by prominent activists, including a leading Afghan human rights group, for the U.S., U.K. and others with a military presence in Afghanistan to undertake similar investigations. Their calls come as U.S. forces draw down from Afghanistan, amid concerns that a near two-decade chapter of foreign force involvement could largely come to a close.

"Only through a series of independent inquiries will we uncover the true extent of this disregard for Afghan life, which normalized murder, and resulted in war crimes," the Afghanistan Independent Human Rights Commission said in a statement.

The Australian inquiry's investigators spoke to 423 witnesses and reviewed more than 20,000 documents and 25,000 images. They listed atrocities that now form the worst wartime incidents carried out by Australian forces, says Neil James, the director of the Australian Defence Association, a security think tank.

"There's no doubt that the Australian Defence Force committed the odd war crime in previous wars," he says. "This is an entirely different situation. These were premeditated, intentional, went for several years and were covered up by the people doing it. That's what makes them particularly shameful."

Human rights advocates say accountability must extend beyond the 19 men referred for criminal investigation.

"Civilian officials and military commanders can still be held criminally liable as a matter of command responsibility. And these are the kinds of abuses they should have known about. It is not enough for them to say they didn't know," says Gossman.

The details of suspected atrocities were redacted from the 463-page Australian report. But some were already public, aired by Australian media after a handful of whistleblowers, including Chapman, came forward. Australian public broadcaster ABC aired footage in March appearing to show an Australian soldier shooting an unarmed Afghan man at close range in a wheat field.

The atrocities identified in the inquiry are probably the tip of the iceberg, says Shaharzad Akbar, the chairperson of the Afghanistan Independent Human Rights Commission. Victims were often isolated in rural areas, sometimes under Taliban control. They either could not reach Afghan authorities or did not trust them.

"They were afraid," Akbar says. "They thought no one would care."

Lalai, an Afghan farmer, tells NPR his family never came forward to report or complain about what he says was the killing by foreign forces of his uncle Wali Mohammad and his brother Zainullah about five years ago in their village in Choghak in Uruzgan province.

He doesn't know who killed his relatives; he only knows they were foreign forces at a time when Australians were operating in the province. He says his loved ones were shot during a night raid on their family compound.

Lalai recalls asking an interpreter with the foreign forces why the soldiers killed his brother and uncle. "He said, 'These guys, they do whatever they want,'" he recalls.

Lalai says the family did not report the killings "because foreigners have the upper hand."

"We couldn't say anything about the foreigners," he explains. "Nobody would have listened to us."

Lalai, who is illiterate and guesses his age is 20, hitched a two-hour ride to the local courthouse to speak to NPR, because there's no cellphone reception in his village. He says he made the effort after all these years because "we want justice."

The Australian inquiry notes that Afghan complaints were often dismissed. According to the report, members of Australia's elite forces shed their standards in repeated, high-pressure combat missions to Afghanistan. They did not have effective oversight and junior soldiers were in the thrall of charismatic commanders.

There was also a growing sense of anger toward military superiors who expected them to risk their lives to capture wanted Afghans for investigation, only for the Afghans to be released days later.

"You started to think, like, oh, we're wasting our time," says Chapman, the former electronic warfare operator. "A few of the guys got heavy-handed," he says, "punching someone or kicking." Or killing.

Now, Chapman says, he hopes the Australian inquiry "inspires Americans to come forward and speak out against everything they did or they witnessed, because I work with Americans who definitely saw some stuff."

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