Otto Warmbier, the 22-year-old student who was returned in an unconscious state last week from North Korea, died Monday, his family said.

"Surrounded by his loving family, Otto died today at 2:20 p.m.," Fred and Cindy Warmbier said in a statement.

Otto Warmbier's doctors at University of Cincinnati Medical Center said last week he had extensive brain damage dating back longer than a year. They said he was in a state of unresponsive wakefulness and was not aware of his surroundings.

The doctors who treated Warmbier said they’d agree not to speak about his outlook, but had said he did not require help breathing.

The Warmbier family did not say how Otto died.

“We would like to thank the wonderful professionals at the University of Cincinnati Medical Center who did everything they could for Otto. Unfortunately, the awful torturous mistreatment our son received at the hands of the North Koreans ensured that no other outcome was possible beyond the sad one we experienced today,” the family said in their statement.

“It would be easy at a moment like this to focus on all that we lost – future time that won’t be spent with a warm, engaging, brilliant young man whose curiosity and enthusiasm for life knew no bounds,” the family added.

“You can tell from the outpouring of emotion from the communities that he touched – Wyoming, Ohio and the University of Virginia to name just two – that the love for Otto went well beyond his immediate family.”

Warmbier’s father Fred said the University of Virginia undergraduate had been “brutalized” by the North Koreans. He was arrested and sentenced to 15 years hard labor after officials said he had attempted to steal a propaganda banner.

“When Otto returned to Cincinnati late on June 13th he was unable to speak, unable to see and unable to react to verbal commands,” the family said.

“He looked very uncomfortable — almost anguished. 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.”

NBC News medical correspondent Dr. John Torres says he believes there was likely a reason North Korea released Warmbier.

“It’s usually pneumonia in a case like this,” Torres said. “He was probably sick and getting sicker.”

Patients who spend prolonged time in bed are very vulnerable to pneumonia.