The family of a 23-year-old Sudanese asylum seeker who died during a Home Office immigration raid are calling for a postmortem into his death to discover the truth about what happened.

Mustafa Dawood escaped persecution in Darfur, Sudan, which has one of the worst records in the world for human rights violations, and went to the UK in 2015.

The circumstances of his death remain unclear. He had been working illegally at Shaftesbury Hand Car Wash in Newport, south Wales, and, during a Home Office raid on 30 June 2018, it was reported he fled to the roof of a neighbouring factory from where he fell and died.

His brother Ahmed Dawood, 29, who travelled to the UK from his home in Colorado in the US when told of the incident, and his cousin Abdulaziz Osman, 35, who lives in Southampton, expected to find him with severe injuries after hearing about the fall. But they said the only visible signs of injury on his body were a small mark on his thumb and another on his chin.

“This is not what we would expect to see after someone fell from a great height,” said Osman. “We have a lot of unanswered questions about Mustafa’s death and a postmortem will help us discover the truth about how he died.”

A spokesman for Newport coroner’s office said a final decision had not yet been made about whether to conduct a postmortem and that sometimes enough medical evidence could be obtained from hospital records, such as x-rays and CT scans, without the need for a postmortem.

“It is heartbreaking that Mustafa managed to escape all the dangers in Darfur and finally reached the UK in 2015 after travelling through dangerous places like Libya, crossing the Mediterranean in a dinghy, travelling through Europe to Calais then hiding under a lorry to get to the UK where he thought he would be safe at last,” said Dawood. “And then he lost his life during a Home Office raid in the UK, the country where he thought he would be safe.”

Dawood and Osman paid tribute to their relative. “He was a quiet and popular boy, he had 4,000 friends on Facebook. He never drank alcohol or smoked and was always trying to help other people.”

Mustafa Dawood arrived in the UK on 30 July 2015 and claimed asylum the same day, based on the fact he was a black African from Darfur, from the Zaghawa tribe, whom the Home Office had confirmed to be at particular risk of persecution from the Sudanese regime. He provided the Home Office with evidence about his origins but his claim was rejected and in April 2018 he received a letter saying the Home Office was terminating his accommodation and support.

“He was working to get money for food,” said Ahmed Dawood. “He didn’t steal someone else’s money. It should not be a crime to work to survive.”

Osman said it was more than two days after Mustafa Dawood’s death that he heard about it from the police in Newport. “The Home Office have a record of me as Mustafa’s next of kin in the UK. I don’t know why they didn’t contact me straight away to tell me about this,” he said.

The family is applying to the Home Office for a visa for Dawood’s mother to visit the UK for the funeral but said they did not know if this would be granted.

“We are totally shocked that after surviving so many dangers Mustafa lost his life here,” said Osman. “The Home Office said things were improving after the Windrush scandal but they did not improve for Mustafa.”

Natasha Thompson, from the charity Inquest, said: “The current approach to asylum seekers in the UK which allows for raids like this is a cause for concern and shame. We hope that Mustafa’s death is looked at in the wider context of the current hostile environment, the influence of which cannot be ignored.’

Yara Nabulsi, from Soas Detainee Support, said: “Taking away the right to work for people, including asylum seekers, forces them into unsafe and exploitative working conditions and leaves them between a rock and a hard place. The threat of being detained, and hostile environment policies, are designed to make life increasingly difficult for those in the immigration process and those not granted legal status by the Home Office.”

A Home Office spokesman said: “Acting on intelligence, immigration enforcement attended Shaftesbury Hand Car Wash, Albany Street, Newport, on Saturday 30 June. During the course of the operation a 23-year-old Sudanese man fell from height and the operation was suspended. Officers at the scene performed CPR until paramedics arrived. The man was transferred by ambulance to hospital, where he later died. Our thoughts are with his family.

“As is the case with any death during the course of a law enforcement operation the police have been informed and the matter referred to the Independent Office for Police Conduct, which is investigating.”