Who Are the Three Other Americans Being Held Captive in North Korea?

Following the death of Otto Warmbier, concern has grown for the three Americans still known to be detained by the North Korean regime.

Warmbier was an American college student who was sentenced to 15 years of prison and hard labor in North Korea for allegedly stealing a political propaganda poster from his Pyongyang hotel in January 2016. He was returned to his home state of Ohio last week, where doctors discovered he had “severe injury to all regions of the brain” and described his condition as “unresponsive wakefulness.”

“It is our sad duty to report that our son, Otto Warmbier, has completed his journey home. Surrounded by his loving family, Otto died today at 2:20 p.m.,” a statement released by his family on Monday read.

“It would be easy at a moment like this to focus on all that we lost — future time that won’t be spent with a warm, engaging, brilliant young man whose curiosity and enthusiasm for life knew no bounds,” the statement continued. “But we choose to focus on the time we were given to be with this remarkable person. You can tell from the outpouring of emotion from the communities that he touched — Wyoming, Ohio, and the University of Virginia — that the love for Otto went well beyond his immediate family.”

Learn more about the three men still being held captive in North Korea.

WATCH: Otto Warmbier Dies After Being Released From North Korean Imprisonment, Family Says

Tony Kim

Tony Kim, also known by his Korean name Kim Sang Duk, taught at the Pyongyang University of Science and Technology for several weeks. Like Warmbier, he was detained at the airport as he was preparing to leave the country in April 2017, according to NBC News.

Aljazeera reported that the official Korean Central News Agency said Kim was being held for “committing criminal acts of hostility aimed to overturn the DPRK [Democratic People’s Republic of Korea].” It added that Kim was “under detention by a relevant law enforcement body which is conducting detailed investigation into his crimes.”

Kim, who is in his 50s, previously worked at China’s Yanbian University of Science and Technology (YUST), on the Chinese border with North Korea.

A former YUST coworker who knew the detainee for 15 years told NBC that Kim was well-liked by teachers and students and enjoyed playing soccer, swimming and biking. The coworker also said Kim and his wife had two sons who had attended a local international school before moving to the United States for a college education.

Kim Hak Song

Kim Hak Song also worked for the Pyongyang University of Science and Technology. CNN reported a statement from the university revealed he had been doing agricultural development work with the school’s agricultural farm.

He was detained in May 2017 on suspicion of “hostile acts” against North Korea.

Kim, who is Korean, was born in China and studied in California.

“He was a very diligent, hard-working man determined to help people in North Korea,” David Kim, a classmate, told CNN. “Professor Kim was a man who would call North Korea as his own country. He went to Pyongyang to devote himself to the development of North Korea’s agricultural technology so that the North can be self-sufficient with food.”

The classmate added that Kim became a citizen of the United States in the 2000s, then returned to China.

“A relevant institution is now conducting a detailed investigation into his crimes,” the official Korean Central News Agency reported at the time of his arrest.

Kim Dong Chul

Kim Dong Chul, now in his early 60s, was born in South Korea and later was a resident of Fairfax, Virginia. He was running a trade and hotel services firm in a special economic zone between China and North Korea.

He was arrested in October 2015, accused of spying on the regime and other crimes. However, his status was unknown until authorities introduced the prisoner to a CNN crew visiting Pyongyang in January 2016.

Kim was sentenced to 10 years of hard labor in April 2016 after making a confession, saying he was paid by South Korean intelligence officers, the BBC reported at the time.