WASHINGTON — American and Czech forces are under investigation for the death of an Afghan commando who was beaten while in NATO custody in western Afghanistan, American and Afghan officials said, demonstrating the tensions that have grown among military forces after 17 years of war.
The commando, Wahidullah Khan, was accused of killing a Czech soldier last month in one of four deadly insider attacks this year by Afghan forces on NATO troops.
One American official said a team from the Army’s 7th Special Forces Group, which helped transfer Mr. Khan to the custody of Czech soldiers, has been withdrawn from Afghanistan as the investigation continues. It is not clear, however, if any American soldiers participated in the beating of Mr. Khan.
Col. Dave Butler, a spokesman for the American-led mission in Afghanistan, acknowledged the investigation but declined to provide details.
The American military “will investigate to determine whether any potential misconduct occurred, and we will hold individuals accountable, as appropriate,’’ Colonel Butler said in a statement on Monday.
Jan Pejsek, a spokesman for the Czech Ministry of Defense, said in an email on Monday that “we strongly deny any such accusations” that Czech troops were involved in Mr. Khan’s death. “There is an ongoing standard investigation regarding the insider attack incident. All respective parties are involved in the procedures,” Mr. Pejsek said.
Officials said Mr. Khan, 19, opened fire on Oct. 22 on a group of Czech soldiers at Shindand air base, a sprawling facility in Herat Province in western Afghanistan. The attack killed Cpl. Tomáš Procházka and wounded two other Czech soldiers.
Within hours, Mr. Khan was arrested by Afghan troops and was taken into custody by Western forces, Afghan officials said. By the time he was returned to Afghan forces, around midnight, he had been beaten and was unconscious, the Afghan officials said.
Mr. Khan died a short time later.
Wakil Ahmad Karokhi, a member of the Herat provincial council, said he did not know whether Czech or American forces struck Mr. Khan.
“From what we know, that soldier died of torture,” Mr. Karokhi said. “He was beaten up before being handed over to Afghan forces.”
A picture of Mr. Khan after his death was given to The New York Times by his family. It shows extensive blunt force trauma to Mr. Khan’s face and head, according to James Gill, the chief medical examiner for the state of Connecticut, whom The Times asked to examine the photo.
“When we washed him, he had no bullet wounds but his entire body was bruised,” said Sayd Rahman, Mr. Khan’s father.
Mr. Khan had been in an Afghan commando unit for about 13 months, according to his brother, Hayaturahman Khan. After graduating from high school, he helped farm in his home district of Kot, driving a tractor. But after Islamic State forces nearly captured the district, Mr. Khan joined the Afghan army and was selected for the elite commando force.
The family found out about his death when a relative saw his photo circulating on social media.
“Nobody told us what happened,” Hayaturahman Khan said. “Nobody has told us who arrested him, who gave him to the foreigners.”
The insider attack came just days after an Afghan guard killed police Gen. Abdul Raziq, an American ally and a national hero to many Afghans, at a meeting in a Kandahar palace. That shooting narrowly missed Gen. Austin Miller, the senior American commander in Afghanistan.
A senior Afghan security official in Kabul said the Afghan government considered Mr. Khan a Taliban infiltrator. Reports from the scene — as well as comments from American officials in meetings with Afghan officials — indicated there may have been a verbal argument that led to the shootout.
Mr. Khan’s family denied that the soldier was connected to the Taliban.
“He’s probably never said hello to the Taliban, let alone being with them,” Hayaturahman Khan said.
Insider attacks are an enduring staple of the war in Afghanistan. The attacks peaked in 2012, accounting for the casualties of 15 percent of all coalition troops who were killed or wounded in Afghanistan that year. The two sides are supposedly close allies, but NATO forces are often armed and wearing body armor when they meet with Afghan troops.
The Czech Republic has roughly 250 soldiers stationed in Afghanistan who have been targeted in recent attacks. Just a week before the insider shooting in Herat, several Czech soldiers were wounded when their vehicle hit a roadside bomb. In August, three Czechs were killed in a suicide bombing outside of Bagram Airfield, the largest American air base in Afghanistan.
In response to demands from Washington, Europeans have maintained or increased troops in recent months. But support for the Afghan war is weak in Europe, where leaders and citizens denounced the American government for torturing prisoners taken from the Afghanistan battlefield after the Sept. 11 terror attacks. Europeans have long been skeptical of the American military detention policies.
There are around 15,000 American troops in Afghanistan, most of them relegated to advisory roles behind the front lines. But Special Operations units, like the team from the 7th Special Forces Group under investigation for Mr. Khan’s death, often fight alongside Afghan troops against the Taliban and other militants.