we do n't know what happened to him and that ’s the bottom line , ” sammarco said .
 
fred and cindy warmbier , center , is escorted at the supreme court in pyongyang , north korea for more than a year .
otto warmbier ’s death on june 19 was due to an unknown injury that occurred more than a year before his death , hamilton county coroner dr. lakshmi sammarco said at a news conference .
north close the hamilton county coroner said wednesday she found no signs of broken bones on otto warmbier ’s body , nor did she find that his teeth had been disfigured while he was imprisoned in north korea as his parents claimed this week .
the coroner convened the session with reporters after fred and cindy warmbier of wyoming appeared on national television tuesday to
a coroner 's report dated sept. 11 shows the cause of death for the university of virginia student as complications from brain - damaging oxygen deprivation through " an unknown insult more than a year prior to death . "
only an external examination of the body rather than a full autopsy was conducted at the request of warmbier ’s family .
the university of virginia student was held by north korea from january 2016 until his release on june 15 .