The answer to that question is different depending on who you ask.
Fred Warmbier, Otto's father, told the hosts of Fox & Friends and CNN Tuesday "it looked like someone had taken pliers and tried to rearrange" Otto's bottom teeth. He said he noticed this while examining his son after the 22-year-old returned to the U.S. in June.
But the Hamilton County Coroner's Office conflicted that account Wednesday.
In a news conference, Coroner Dr. Lakshmi Sammarco said she did not see "any evidence of trauma" to Otto's teeth upon his return from North Korea.
Fred and Cindy Warmbier spoke to national news outlets this week for their first interviews since their son's funeral in June. They described the horror of seeing Otto return from captivity in a degraded state.
"He was on a stretcher, jerking violently, making this howling, involuntary, inhuman sound," Fred said. "His head was shaved, he had a feeding tube in his nose. He was blind, he was deaf. As we looked at him and tried to comfort him, it looked like someone had taken pliers and tried to rearrange his bottom teeth. He reached a 104 degree fever and he had a large scar on his right foot."
Sammarco said she was surprised by the Warmbier's statements.
She said her office performed an external examination, went through extensive medical imaging and conducted a post-mortem CT scan of Otto’s body.
A forensic dentist examined the images, specifically the lower teeth and mandible, Sammarco said.
“He agreed with us that there was no evidence of trauma to the lower teeth or mandible on the imaging or by physical examination,” Sammarco said.
Watch Sammarco's full news conference in the player below:
Sammarco said the "jerking" and "howling" Fred Warmbier described would be consistent with someone who suffered severe brain damage.
"In patients that have chronic ... brain damage, there are involuntary movements and sounds and grunts and so forth that happen, and when you’re not familiar with patients that have that kind of brain damage, I think it’s going to be alarming for a lot of people," Sammarco said.
But Sammarco would not comment specifically about what the Warmbiers said.
“They’re grieving parents, and I really can’t make comments about what they said or their perception," Sammarco said. "All I can tell you is, we here in this office depend on science for our conclusions ... if we saw something that was significant and we could back it up ... we would do that.”
Dr. Daniel Kanter, director of Neurocritical Care Program at the University of Cincinnati Medical Center, said his coma was likely caused from cardiac or respiratory arrest, which decreases blood supply and results in the death of brain tissue.
Dr. Jordan Bonomo said respiratory arrest is the main cause of cardiopulmonary arrest in a young person, and respiratory arrest is typically caused by “intoxication or traumatic injury.”
“We do see respiratory arrests from overdose -- from medication overdose -- intentional or otherwise,” Bonomo said. “It would be inappropriate for me to speculate about the intent or whether this was a misadministration of a medication.”
Doctors found no evidence of trauma after examining all of Otto's bones. Kanter said scans did not show any acute or healing fractures, including scans of his skull.
Earlier reports of Otto's condition stated North Korean officials claimed he had contracted botulism, and he fell into a coma after he was given a sleeping pill.
Dr. Brandon Foreman, associate director for Neurocritical Care Research, said there was no evidence that would suggest “active or chronic” botulism -- a nerve-damaging bacteria.
Kanter said there is no way to tell for certain how Otto sustained his injuries. Kanter also said Otto's "skin was in good condition, and he was well-nourished when he arrived at our facility."
Sammarco reiterated Otto’s body and skin were in “excellent condition” for someone who was bedridden.
“Well I think most people are familiar with bedridden people, it takes a lot of care and a lot of consistent rotating and conditioning of the skin to make sure that you don’t have skin breakdowns, so I’m sure that he had to have round-the-clock care to be able to maintain the skin in the condition it was in,” Sammarco said.
Along with honoring the family’s wishes, Sammarco said her office decided not to perform an autopsy because they felt like “nothing significant was going to be gained,” considering whatever happened to Otto happened a year before his return to the U.S.
How exactly did Otto sustain brain damage? Sammarco, like many others, said she couldn’t answer that question.
“We don’t know what happened to him to cause that brain damage over a year before he died … at this point we’re never going to know ... unless the people that were there at the time it happened come forward and say, ‘This is what happened to Otto,’” Sammarco said.