Fred and Cindy Warmbier watch as their son Otto, is placed in a hearse after his funeral, Thursday, June 22, 2017, in Wyoming, Ohio. His parents released a statement that said his death was the inevitable result of "the terrible torturous mistreatment our son received at the hands of the North Koreans".

Former NBA star Dennis Rodman made an appearance on Friday's "Good Morning America" and essentially took credit for North Korea's release of Otto Warmbier, an American college student imprisoned in the country for 18 months.

Doctors who examined Warmbier upon his arrival in the US described his condition as a state of "unresponsive wakefulness", and indicated he suffered a "severe neurological injury" of unknown cause. He was sentenced to 15 years of hard labor for trying to steal an item bearing a propaganda slogan from his hotel, North Korea state media said. KCNA said the North dealt with him according to its domestic laws and worldwide standards.

US Secretary of State Rex Tillerson said he held North Korea responsible for the student's death.

Warmbier died Monday, just days after he returned to the United States, and his funeral was held in his hometown in Ohio Thursday. "To make it clear, we are the biggest victim of this incident", he said, calling the accusations of abuse "groundless".

Warmbier was buried Thursday in a funeral attended by thousands in his native OH town.

The spokesman also blamed the Obama administration for failing to act sooner to help Warmbier, saying the 22-year-old University of Virginia undergrad was "a victim of policy of 'strategic patience.'" The Obama administration, the spokesman said, never asked for his release. He recalled that the United States citizen, who had admitted his guilt, was sentenced by the court to hard labor "for subversive activities against North Korea".

The article said South Korea was tarnishing North Korea's image with "slanderous talk about cruel treatment and torture". But officials at the University of Cincinnati Medical Center, where Warmbier was treated after his return, said they had found no trace of the disease.

Otto Warmbier, in a coma, is transferred from a medical transport airplane to an awaiting ambulance at Lunken Airport in Cincinnati, Ohio, US. "I look at the friendship about him", Rodman said.

He blasted South Korea, accusing it of seeking to exploit Warmbier's death to press its own demand for the release of six South Korean detainees. These Americans are then used as pawns in diplomatic negotiations with the U.S. Over the last decade, at least 17 U.S. citizens have been detained in North Korea, and three remain in captivity.