The University of Virginia student was held prisoner in North Korea while travelling.
"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.
During trial in March 2016, which reportedly lasted less than an hour, Mr Warmbier confessed to stealing the poster.
He won an award at the highly rated high school, and was on the soccer team, among other activities. Warmbier, an American college student who was released by North Korea in a coma last week after nearly a year and a half in captivity, died Monday, June 19, his family said.
Government officials in Seoul said that North Korea has yet to respond to their demands to check on the state of its six nationals detained in the North.
In the CBS interview, Moon said that while "we can not know for sure that North Korea killed Mr Warmbier".
The B-1B's flight training also follows controversial remarks by Moon Chung-in, a special adviser to South Korean President Moon Jae-in on unification, security and foreign affairs who said Seoul may decrease the deployment of US strategic assets in the region and the number of the allies' combined military drills if North Korea frozes its nuclear and missile development.
It says it takes around 2,000 travelers from other countries to North Korea every year, only 20% of whom are American.
Hearing scheduled on release of Cosby jury names
Bill Cosby exits the Montgomery County Courthouse after a mistrial was declared in Norristown , Pa., Saturday, June 17, 2017. A judge will hear arguments on whether the names of the jurors at Bill Cosby's sexual assault trial should be made public.
He says "if people are that stupid that they still want to go to that country, then at least they assume the responsibility for their welfare".
Warmbier's death affects South Korea's efforts to restart its dialogue with North Korea, Moon told CBS News' Norah O'Donnell, "we must now have the perception that North Korea is an irrational regime".
McCain is the Republican chairman of the Armed Services Committee.
Three more U.S. citizens are now being held by North Korea. His parents said he died on Monday.
His parents claim he was given "awful torturous mistreatment", according to the BBC.
Doctors at the University of Cincinnati Medical Centre said that while Warmbier had been breathing on his own, he was severely brain damaged and showed no awareness of his surroundings and made no "purposeful movements or behaviours".
Otto Warmbier, an American college student who was released by North Korea in a coma last week after more than a year in captivity, died on Monday, his family said.
Following the death of US student Otto Warmbier, North Korea faced new calls to release the remaining detainees from the usa and South Korea Tuesday - as President Trump condemned the "brutality" of the kingdom's regime.