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With three simultaneous investigations underway, authorities are likely months from deciding whether a U.S. airstrike on a Doctors Without Borders hospital in Afghanistan was a war crime.

The likelihood of an international prosecution is remote, experts say.

But the case might lead to military trials in both countries, where prosecutors could seek convictions for the decisions that led an American AC-130 gunship to open fire on a trauma center during fighting for the city of Kunduz, killing at least 30 people, including 13 charity staffers.

In the end, if anyone is found criminally liable for the Oct. 3 bombing, it will be mid- to low-level operators who requested and carried out the airstrikes, experts said. Ranking officers typically don't get prosecuted in such cases; they tend to get demoted or forced into retirement.

But first, investigators must navigate a swamp of shifting accounts.

Related: Obama Calls Doctors Without Borders to Apologize for Deadly Hospital Airstrike

The U.S. military has changed its explanation of the strike several times.

In the hours following the strike, the Pentagon said the bombing had targeted "individuals threatening with force," and that American personnel had come under fire. Then the military backtracked, saying U.S. forces were not attacked, but that Afghan forces — who assert that Taliban fighters were hiding in the hospital — asked for the strike.

The U.S. military eventually acknowledged that the strike had been approved "within the U.S. chain of command," which was responsible for vetting the Afghan request. President Obama called the president of Doctors Without Borders to apologize.

But Doctors Without Borders is not satisfied.

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The U.S. military, Afghan military and NATO have all launched investigations, but the charity says they can't be trusted to conduct fair reviews. It has asked for an independent examination by the International Humanitarian Fact Finding Commission.

Such a review remains an extreme long shot, experts say. Neither the United States or Afghanistan are signatories to the commission, which means that they would have to agree to being investigated.

Also unlikely is an investigation by the International Criminal Court in the Hague, which prosecutes allegations of war crimes. The United States is not a party to the ICC, which means its military personnel are not under its jurisdiction, experts say. But Afghanistan is. That opens a possibility, however small, that the ICC could open its own review of the case.

Which brings things back to the military courts.

Related: Another Doctors Without Borders Staffer Confirmed Dead in U.S. Airstrike

The United States has historically pursued allegations of wartime atrocities through courts-martial. The last major case was the 2012 murder of Afghan villagers by U.S. soldier Robert Bales, who was sentenced to life in prison. But Bales was not following orders; he was a rogue soldier.

The case with more similarities, experts say, is the Abu Ghraib prisoner-torture scandal, in which several soldiers were convicted, some of whom went to prison. No commanders were prosecuted, although defense lawyers and humanitarian groups have said blame belongs much farther up the ranks of the U.S. military.

Kunduz investigators will be faced with a similar challenge. They'll have to determine not only who called in the strike, but who approved the request, and who made it happen, said Devin Pendas, who researches war crimes trials at Boston College.

"This was clearly done on orders," Pendas said. "Some kind of decision was made at some point in the chain of command that this was a legitimate military target."

The Kunduz proof will likely hinge on the "doctrine of proportionality," a legal concept that, in the context of alleged war crimes, weighs the need for military action against the damage that action might do to the civilian population.

"If a party knew it was a hospital and intentionally targeted it without a militarily reason to do so it is most likely a war crime," David Crane, a professor of international criminal law at the Institute for National Security and Counterterrorism at Syracuse University, said in an email.

To answer that question, investigators will need to determine whether the U.S. and Afghanistan forces knew they were attacking a hospital and whether the soldiers believed it would advance its goal of defeating the Taliban.

Doctors Without Borders has said it told the U.S. military its hospital's GPS coordinates, and Army Gen. John Campbell, the coalition's top commander in Afghanistan, has said it would "never intentionally target a protected medical facility."

But it remains unclear whether the U.S. military believed Taliban were operating inside the hospital, or whether the gunship came under fire — either of which could be justifications for the attack, experts said.

"It could come down to a judgment call," said Harry Rhea, a war crimes investigator who teaches international criminal law at Florida International University.

Blaming the Afghans for requesting the strike doesn't necessarily absolve the U.S. military, Rhea added.

"It could be considered reckless, or at least negligent, to not vet it any further," he said.

Pendas predicted that, in the end, the U.S. military wouldn't prosecute anyone, although low-level Afghan forces might be found criminally responsible.

"But this will probably result in people losing their jobs — and a change in policy for how we review requests for airstrikes coming from allied forces."