The American college student who was released by North Korea in a coma suffered a “severe neurological injury,” according to a spokesperson for an Ohio hospital.

Otto Warmbier is in stable condition after arriving at the hospital two days ago, Kelly Martin of the University of Cincinnati Medical Center said Thursday.

Doctors plan a news conference on campus for later Thursday.

His father, Fred Warmbier, said Thursday he does not believe North Korea’s explanation that the coma is the result of botulism and a sleeping pill.

Warmbier said they’re relieved their son is home in the arms of those who love him, but angry he was so brutally treated for so long.

“Otto has been terrorized and brutalized for 18 months by a pariah regime in North Korea,” the father said in an interview with Tucker Carlson of Fox News scheduled to air Thursday night.

Otto Warmbier, a 22-year-old University of Virginia student, was medically evacuated from North Korea and flown to Cincinnati late Tuesday. He was then taken by ambulance to a hospital.

Warmbier was serving a 15-year prison term with hard labour in North Korea after tearfully confessing to trying to steal a propaganda banner while on a visit 

Former New Mexico governor Bill Richardson, also a former U.S. ambassador to the United Nations, said there should be an investigation into what led to this “tragic situation.”

Richardson, a Democrat, credited the Department of State with securing Warmbier’s return from North Korea without any preconditions, but said a forceful response from the U.S. government would be required “if it’s determined that there was a coverup, and Otto’s condition was not disclosed and he didn’t get proper treatment.”

Such detentions in the totalitarian nation have added to tensions between Washington and Pyongyang.

Three American citizens remain in custody:

  • Kim Dong Chul, a businessman.
  • Tony Kim, a university professor.
  • Kim Hak-song, a university employee.

Hyeon Soo Lim, a pastor who has lived in the Toronto area for three decades after immigrating from South Korea, has been detained in North Korea since 2015. He had made dozens of trips to North Korea before his detention, which were for humanitarian aid purposes, according to his church and family.

The U.S. government accuses North Korea of using such detainees as political pawns. North Korea accuses Washington and South Korea of sending spies to overthrow its government.

U.S. Secretary of State Rex Tillerson said Tuesday his department was continuing “to have discussions” with North Korea about the release of the other three imprisoned Americans.