It may never be known, but there are some clues — as well as widespread speculation.
The University of Virginia student was medically evacuated from North Korea last week, more than a year after a court sentenced him to 15 years in prison with hard labor for allegedly trying to steal a propaganda banner.
His family said it was told he fell into a coma soon after his March 2016 sentencing after contracting botulism and taking a sleeping pill. Doctors in Cincinnati said they found no active sign of botulism or evidence of beatings. They say he had severe brain damage but they don’t know what caused it.
Some observers believe that North Korea became worried because Warmbier’s condition suddenly worsened.
“North Korea sent him back to the United States before he died because more questions would have been raised about his death and the situation would have gotten worse if it had returned his dead body,” said Cheong Seong-jang, an analyst at the private Sejong Institute in South Korea.
Others believe it is unlikely that North Korea intentionally harmed Warmbier because he was valuable as a political pawn. Poor hygienic conditions, diet or bad medical care may have been responsible for a coma that North Korean doctors couldn’t handle.
Or maybe North Korea concealed his medical condition for so long in the hopes that he’d recover.