The kid was arrested for allegedly stealing a poster, according to other reports

See this at Wikipedia.

Otto Warmbier's family rebukes Trump, says Kim Jong Un is responsible for son's death

After a second summit with Kim in Vietnam, President Trump said Thursday he does not hold the North Korean dictator responsible for Warmbier's death.

"He tells me that he didn't know about it and I will take him at his word," Trump said during a news conference, also claiming Kim "felt very badly. 

But he knew the case very well, but he knew it later."

. . . .

During his Thursday news conference in Vietnam, Trump told reporters he believed Kim's denial in part because it would not be in Kim's interest for Warmbier to wind up in a coma.

"I don't think that the top leadership knew about it," Trump said. 

"I don't believe that he (Kim) would have allowed that to happen."

Trump's whitewash ignored the tight control that Kim maintains over his country's internal affairs as its supreme leader, particularly when it comes to sensitive matters such as the imprisonment of an American citizen.

. . . .

Kim oversees one of the world's most repressive regimes, one that human rights groups say includes concentration camps, starvation and carries out medical experimentation on human subjects. 

The UN estimates that North Korea has 80,000 to 120,000 people in its gulags.

Otto Warmbier was a University of Virginia student when he was detained in January 2016 during a brief sightseeing tour of the reclusive state. 

He was held captive by the North Korean regime for over a year, before being released back to the US in June 2017. 

Then 22 years old, Warmbier returned home to Ohio in a vegetative state -- blind, deaf, and having sustained severe brain damage from his time in detention. 

He died on June 19, 2017, days after the Trump administration had secured his return.

. . . .

Trump's whitewash ignored the tight control that Kim maintains over his country's internal affairs as its supreme leader, particularly when it comes to sensitive matters such as the imprisonment of an American citizen.

Kim oversees one of the world's most repressive regimes, one that human rights groups say includes concentration camps, starvation and carries out medical experimentation on human subjects. 

The UN estimates that North Korea has 80,000 to 120,000 people in its gulags.