Mohommad Nazeer Paktyawal, who was living in a Dallas suburb with his wife and six children while his asylum case remained pending, was arrested by federal agents outside his apartment on Friday morning while taking his children to school, AfghanEvac president Shawn VanDiver said in a statement.
AfghanEvac supports Afghan allies and refugees to honour commitments made to those who served alongside US forces.
Paktyawal died of unknown causes on Saturday, VanDiver said on X.
Paktyawal, 41, is at least the 12th person to die in ICE detention this year under US President Donald Trump's immigration crackdown.
In 2025, 31 people died after being detained by ICE, a two-decade high.
ICE has played a central role in Trump's policy of mass deportations.
In a statement on Sunday, ICE said Paktyawal was eating breakfast when medical staff noted that his tongue had become swollen, prompting a medical response.
He was declared dead only after multiple attempts at resuscitation, the agency said.
The agency said it "is committed to ensuring that all those in custody reside in safe, secure, and humane environments".
According to VanDiver, Paktyawal's family was told that he was taken to a hospital in Dallas on the night of his arrest and was still alive the following morning, but died shortly after.
AfghanEvac called for an immediate investigation.
"It is highly unusual for an otherwise healthy 41-year-old man to die less than a day after being taken into government custody," VanDiver said.
Paktyawal, a former Afghan special forces soldier who had worked alongside US Army Special Forces since 2005, was evacuated from Afghanistan with his family in 2021 when the US withdrew its forces.
Paktyawal had worked in the Dallas area at an Afghan halal market and was the primary provider for his family, including an 18-month-old baby, VanDiver said. He had been living in Richardson, Texas, VanDiver said.
The number of people detained by ICE has risen to record levels during Trump's immigration crackdown. ICE had some 68,000 people in custody as of early February.
More than 70,000 Afghans entered the US under former president Joe Biden's Operation Allies Welcome initiative following the Taliban takeover of Kabul in 2021, according to the Department of Homeland Security.
US agencies under Trump have moved to terminate temporary protected status previously granted by the US government for humanitarian reasons to some 14,600 Afghans, opening them up to deportation.
