Afghan ally's death in Dallas ice custody ruled accidental, family demands answers

New details are being released about the death of an Afghan father and former U.S. military ally who died in U.S. Immigration and Customs Enforcement custody in Dallas in March.

Death certificate says allergic reaction caused fatal anaphylaxis

A new document states that former Afghan ally Mohammad Nazeer Paktiawal died from an allergic reaction, less than 24 hours after his detainment.

Nearly four months after he died in ICE custody, his family is demanding answers on what happened to him inside a Dallas detention facility.

"They don't know that their dad is never going to come back home for the rest of their life. What we're going through, nobody can imagine that," said his brother, Naseer Paktiawal. "Someone in that building knows what happened to my brother. I want to know. I want them to say it."

A death certificate Paktiawal's family provided states the 41-year-old had an allergic reaction to an unidentified substance, which caused anaphylaxis and triggered his asthma. Paktiawal's death is the first in ICE custody this year to be ruled an accident.

Family seeks release of autopsy report amid ongoing investigation

The family, along with advocates are now calling on Texas officials to release Paktiawal's autopsy report. Dallas County is withholding the report, at the request of ICE, because they say its release could interfere with an ongoing criminal investigation

"ICE should state on the record what pending federal criminal investigation it is citing and why that objection should outweigh the family's right to know how their family member died and why the government's own paperwork can't even get the date right," said Shawn Vandiver, president of AfghanEvac.

CBS News Texas contacted the Dallas County District Attorney's office, but a spokesperson said this is a federal law enforcement matter. We also reached out to ICE, which referred us to a previously released statement about Paktiawal's death, which said he was hospitalized after experiencing shortness of breath and chest pain in a holding room, and that he died the next day at Parkland Hospital, his tongue had become swollen, prompting a medical response.

Lawmakers question ICE's handling of the case 

U.S. Sen. Richard Blumenthal is one of two lawmakers who spoke out on behalf of the family Monday, asking for answers.

"What's happening here smacks of a cover-up?" Blumenthal said. "What are they hiding? Why are they refusing to disclose the autopsy report?"

Family disputes methamphetamine finding on death certificate

The death certificate also lists the toxic effects of methamphetamine, heart disease, and cigarette smoking as contributing factors to Paktiawal's death, but his brother questions those findings, saying Paktiawal never used methamphetamine and had quit smoking years ago.

"If my brother had never used that drug in his life, how did it get into his body, while he was in ICE custody, in an ICE custody building, what accident are they talking about?, Naseer said.