North Korea releases Otto Warmbier, but 3 other Americans still remain behind bars

The three American citizens being detained in North Korea

Here are the three American citizens still being detained in North Korea and why.

The release of 22-year-old college student Otto Warmbier from a North Korean prison on Tuesday leaves three American citizens still behind bars in the volatile country.

In the past, North Korea has generally quickly released any American citizens it detained – waiting at most for a U.S. official or statesman to come and to personally bail out detainees. But if Warmbier’s more than two years in prison – out of a 15-year sentence – is any indication, that trend appears to be changing.

While U.S. government officials have lobbied for the release of these prisoners, little progress has been made as relations between Washington and Pyongyang deteriorate amid the latter’s continued missile tests and refinement of nuclear weapons.

Here is a look at the three American citizens being held in North Korea:

Kim Hak-song

North Korean officials announced in early May that Kim Hak-song – who worked at the Pyongyang University of Science and Technology (PUST) – on charges of unspecified hostile acts against the country.

Very little is known about Mr. Kim besides the fact that he worked at PUST – a university founded in 2010 evangelical Christians and funded in large part by churches in the U.S. and South Korea. The majority of students at the school are children of North Korea’s elite.

Reuters reported that a message by Kim Hak Song dated February 2015 on the website of a Korean-Brazilian church in São Paulo said he was a Christian missionary planning to start an experimental farm at PUST and was trying to help the North Korean people learn to become self-sufficient.

Tony Kim (also goes by his Korean name, Kim Sang-duk)

(Video screen grab)

Just days before the arrest of Kim Hak-son, officials in North Korea detained Tony, according to Park Chan-mo, the chancellor of PUST, as he was trying to leave with his wife on a flight to China.

The Swedish embassy in Pyongyang said Sunday it was aware of a Korean-American citizen being detained recently but could not comment further. The embassy looks after consular affairs for the United States in North Korea because the two countries do not have diplomatic relations.

The State Department also said it was aware of the report about a U.S. citizen being detained, but declined further comment "due to privacy considerations."

Park said he was informed that the detention had "nothing to do" with Kim's work at the university but did not know any further details.

Kim previously taught Korean at the Yanbian University of Science and Technology in Yanji, China, not far from the North Korea border, said the school's Communist Party committee secretary.

As of Monday morning, North Korea's official media had not reported on the detention and there so far have been no details on why Kim was detained.

Kim Dong Chul

ARCHIVO - En estas fotografía de archivo, los estadounidenses Otto Warmbier, a la izquierda, y Kim Dong Chul, son retirados en fechas distintas de un tribunal en Pyongyang, Corea del Norte. La fotografía de Warmbier tiene fecha del 16 de marzo de 2016 y la de Dong Chul, del 29 de abril del mismo año. Corea del Norte detuvo al estadounidense Tony Kim, que también usa su nombre coreano de Kim Sang-duk, dijeron funcionarios el domingo 23 de abril de 2017. Con el arresto de Kim aumentaron a tres los estadounidenses detenidos en Corea del Norte. (AP Foto/Archivos) (AP Photo/Archives)

The plight of the Korean-American businessman is probably the most hazy case of all the Americans being held in North Korea.

TIMELINE OF EFFORTS TO FREE OTTO WARMBIER

A former resident of Virginia, Kim was living in China with his wife and operating a business in a special economic zone of North Korea when he was detained in October 2015 while in the city of Rason. His detainment was not made public until North Korean officials introduced him to a visiting news crew and allowed him to be interviewed through an interpreter.

It was later revealed that Kim had been detained on suspicion of engaging in spying and stealing state secrets. He was sentenced to 10 years in prison with hard labor after a brief trial in Pyongyang. North Korea's Supreme Court found Kim guilty of espionage and subversion under Articles 60 and 64 of the North's criminal code.

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When he was paraded before the media in Pyongyang last March, Kim said he had collaborated with and spied for South Korean intelligence authorities in a plot to bring down the North's leadership and had tried to spread religion among North Koreans before his arrest.

South Korea's National Intelligence Service, the country's main spy agency, has said Kim's case wasn't related to the organization in any way.