What happened to Otto? Strange twist in death of North Korea jailed US student

The mystery surrounding the death of US student Otto Warmbier has only deepened after the emergence of details from his coroner's report.

The latest revelations come after an emotional television interview from his parents Fred and Cindy Warmbier on Tuesday who claimed that their son had been tortured by North Korean officials.

But those claims have now been thrown up in the air after the findings of an examination by The Hamilton County Coroner’s Court on June 19 were released.

Dr Gretel Stephens found that his body was that of a “well-developed, well-nourished adult man," News Corp reported.

He also listed the cause of death as brain damage due to an abscence of oxygen from an injury “more than a year prior to death,” while the manner of death is written as “undetermined" as a full autopsy was previously rejected by the family.

There was also several scars across his body indicating medical treatment including a scar consistent with that of a tracheostomy.

The document states that “the teeth are natural and in good repair”, contradicting claims his father made that his teeth 'looked like someone had taken a pair of pliers and rearranged' them.

His parents appeared on Fox News amid an escalating war of words between the Trump administration and North Korea, claiming the rogue state's people are "terrorists".

They also suggested their son, who spent more than a year detained in North Korea, was howling, "jerking violently" and "staring blankly" when he returned home on a medical flight.

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Otto Warmbier's father said they wanted to speak out about their son’s condition after hearing North Korea claim to be victims that have been picked on.

He was also adamant his son was severely mistreated physically while imprisoned in the rogue state.

"They kidnapped Otto. They tortured him. They intentionally injured him," he said.

Otto was sentenced to 15 years of hard labour in March 2016 for allegedly stealing a propaganda poster.

His parents described the horrifying condition his family found him in when they went aboard an air ambulance that arrived on June 13 in Cincinnati.

They said Otto, a 22-year-old University of Virginia student, was howling, making an "involuntary, inhuman sound" and was blind and deaf with his head shaved.

The parents described their son as "staring blankly into space jerking violently".

Fred Warmbier said his son’s mouth "looked like someone had taken a pair of pliers and rearranged his bottom teeth".

Following their appearance on television, President Trump labelled their account as "a great interview" on Twitter shortly after claims from a North Korean official claiming Trump had declared war with the nation. That has since been denied by the White House.

He echoed Mr Warmbier's accusations, suggesting North Korea had abused an American student who had been held captive in North Korea, saying the young man had been "tortured beyond belief".

Trump had previously blamed Pyongyang's "brutal regime" for Warmbier's plight but it was the first time the president publicly accused North Korea of torture in the case.

North Korea has denied mistreating the young man.

The Warmbiers now want North Korea listed as a state sponsor of terrorism.