CHICAGO, United States (AFP) — Otto Warmbier, the US student released by North Korea in a coma last week after more than a year in detention, has died, his family said Monday.

The 22-year-old, who had suffered severe brain damage, was medically evacuated to the United States on June 13. He died Monday at 2:20 pm (US time), surrounded by relatives in his home town of Cincinnati, Ohio.

“It is our sad duty to report that our son, Otto Warmbier, has completed his journey home,” his family said in a statement.

“The awful torturous mistreatment our son received at the hands of the North Koreans ensured that no other outcome was possible,” they added.

Pyongyang said that Warmbier fell into a coma soon after he was sentenced in March of last year for stealing a political poster from a North Korean hotel. The regime claimed the young man fell into a coma after contracting botulism and being given a sleeping pill.

Doctors treating Warmbier said he had suffered extensive tissue loss in all regions of his brain, but showed no signs of physical trauma. Medical tests offered no conclusive evidence as to the cause of his neurological injuries, and no evidence of a prior botulism infection.

They said Warmbier’s severe brain injury was most likely — given his young age — to have been caused by cardiopulmonary arrest cutting the blood supply to the brain.

Warmbier’s father, Fred, lashed out at Kim Jong-Un’s authoritarian state last week, telling a news conference, “there is no excuse for any civilized nation to have kept his condition secret and denied him top-notch medical care for so long.”

In their statement Monday, Otto’s family said they believed he had found a peace of sorts after being flown home.

“When Otto returned to Cincinnati late on June 13th he was unable to speak, unable to see and unable to react to verbal commands. He looked very uncomfortable — almost anguished,” they said.

“Although we would never hear his voice again, within a day the countenance of his face changed — he was at peace. He was home and we believe he could sense that,” they added.

“We thank everyone around the world who has kept him and our family in their thoughts and prayers. We are at peace and at home too.”

The university student, who had been on a tourist trip, was sentenced to 15 years hard labour, a punishment the US decried as far out of proportion to his alleged crime, accusing the North of using him as a political pawn.

President Donald Trump had urged the nation to pray for Otto Warmbier, describing his ordeal as a “truly terrible thing.”

Warmbier’s release came amid mounting tensions with Washington following a series of missile tests by Pyongyang, focusing attention on an arms buildup that Pentagon chief Jim Mattis has dubbed “a clear and present danger to all.”