Mr Warmbier graduated from the school in the Cincinnati suburb of Wyoming in 2013.
Todd Siler, who taught Warmbier in high school, said his youngest daughter, an 11-year-old, watched the doctors talking last week about Warmbier, who had been her swimming coach.
Irked by frequent provocations by North Korea, the United States has said that China has a responsibility to exert much greater pressure on North Korea to prevent escalating tensions. Warmbier was buried in Cincinnati, Ohio, his hometown, today.
Popular University of Virginia student Otto was hospitalised with brain damage while in a North Korea labour camp. He spent more than a year in the North Korea prison after being sentenced to 15 years of prison and hard labor for allegedly stealing a political propaganda poster from his Pyongyang hotel in January 2016. The service was conducted by a rabbi and lasted about one hour.
The extent to which Beijing can influence Pyongyang is key in trying to defuse the North Korean crisis, and Tillerson's remarks came the day after US President Donald Trump appeared to suggest Chinese President Xi Jinping (習近平) had come up short in efforts to lean on North Korean leder Kim Jong-un's regime.
His parents had no word of him since March 2, 2016, until earlier this month, when North Korean officials disclosed that he was in a coma, and had been for more than a year.
"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. Doctors said he was suffering from a catastrophic brain injury, probably sustained shortly after his trial.
"He shows no signs of understanding language ..." About 1,000 Americans visit each year, roughly one-fifth of all tourists to North Korea.
"Our thoughts and prayers are with Otto's family and friends, and all who loved him".
"Unfortunately, the bad torturous mistreatment our son received at the hands of the North Koreans ensured that no other outcome was possible beyond the sad one we experienced today", the family said in a statement.
"The family's objection to an autopsy was honored and only an external examination was performed", the coroner's office said in a statement Tuesday night.
But by Thursday, Eric Cortellessa of The Times of Israel had gotten in touch with Mickey Bergman of The Richardson Center, an organization run by the former governor of New Mexico, Bill Richardson, that negotiates the release of hostages, including Warmbier, with a particular focus on North Korea.
Defence Secretary Jim Mattis said Trump's commentary "represents the American people's view of North Korea right now".
In addition to asking China to do more to rein in North Korea's evolving nuclear and missile threats, the South Korean president said he also planned to ask Xi to remove China's apparent retaliatory measures against South Korean firms and products.