An Ohio college student recently released from imprisonment in North Korea was reportedly beaten numerous times during his time behind bars. Twenty-two-year-old Otto Warmbier, who arrived in Cincinnati late Tuesday before being rushed to a hospital, was serving out a 15-year prison term for attempting to steal a propaganda poster when U.S. officials secured his release earlier this week. His father, Fred Warmbier, told Fox News’ Tucker Carlson on Wednesday that his son was “brutalized” while in North Korean custody. No further details were released on the extent of Warmbier’s injuries, but his parents say they plan to hold a press conference on Thursday. The University of Virginia student’s family had initially said they were told he was in a coma since his trial in March 2016, but the cause of his deteriorating health has remained a mystery. North Korean authorities claimed he contracted food poisoning. A senior U.S. official said Wednesday, however, that authorities had received intelligence reports suggesting Warmbier was repeatedly beaten while serving out his sentence, according to The New York Times. The news comes amid heightened tensions between Pyongyang and Washington, with at least three other Americans still held in North Korean prisons.