The family of freed American prisoner Tony Kim thanked President Trump for “engaging directly with North Korea.” The statement was released as Kim and two other former prisoners flew home with Secretary of State Mike Pompeo on Wednesday.

All three were arrested on vague charges of subversion and treated abominably by North Korea during their captivity. The White House said on Wednesday that all “appear to be in good condition” after their ordeal and were able to board the plane home without requiring assistance. All three share the common surname “Kim” but are not related. All three have Christian religious affiliations.

The statement from Tony Kim’s family reads:

We are very grateful for the release of our husband and father, Tony Kim, and the other two American detainees. We want to thank all of those who have worked toward and contributed to his return home. We also want to thank the President for engaging directly with North Korea. Mostly, we thank God for Tony’s safe return.

We appreciate all of the support and prayers of friends and even strangers during this challenging year. You are dear to our hearts. We ask that you continue to pray for the people of North Korea and for the release of all who are still being held. Thank you.

Tony Kim was arrested at the Pyongyang airport on April 22, 2017, while seeking to depart after a month of teaching accounting at the Pyongyang University of Science and Technology, the extraordinary private school founded by Christian groups and tolerated, but frequently hassled, by the communist regime. South Korean media also reported at the time that he helped to build orphanages in North Korea during his stay.

The North Korean regime claimed Kim was engaged in “hostile criminal acts with an aim to subvert the country.”

“Invited to Pyongyang University of Science and Technology (PUST) to teach accounting as a professor, he was intercepted for committing criminal acts of hostility aimed to overturn the DPRK not only in the past but also during his last stay before interception,” North Korean media declared.

The university said it did not believe Kim’s arrest was related to his work there. It was widely supposed that he was taken prisoner due to rising tensions between North Korea and the United States. His wife was with him when he was detained, but she was allowed to return to the United States.

Kim’s oldest son, Sol, said in a plea for his release on March 2018 that “no explanation was given” for his father’s arrest, he was never formally tried with any crime, and the family “had no contact with him since.” The family’s only information about him came from a brief sighting during the release of fellow American prisoner Otto Warmbier, who died shortly after:

Detainee Kim Hak-song also worked for the Pyongyang University of Science and Technology. He was arrested on May 6, 2017, under suspicion of “hostile acts” against the North Korean government, which promised a “detailed investigation” would be conducted.

Kim Hak-song is a self-described Christian missionary who conducted agricultural research at the Pyongyang University of Science and Technology.

According to a Chosun Ilbo profile from March 2018, Kim Hak-song was born in China to Korean parents, studied theology in Los Angeles, obtained American citizenship in 2008, and went to work for PUST in Pyongyang in 2014. He was arrested while “waiting for a train bound for his hometown of Dandong, China.”

Kim Dong-chul was arrested in October 2015 and accused of working as a spy for South Korea. He was supposedly taken into custody while receiving a USB drive full of classified information from a North Korean defector. He was sentenced to ten years of hard labor in an April 2016 ruling by the North Korean Supreme Court from which no appeal was allowed roughly a month after a similar sentence was imposed on Otto Warmbier.

A North Korean defector and missionary who met with Kim Dong-chul in the United States in 2007 said he presented himself as “a missionary working on North Korea and sending stuff from China into the North to help poor North Koreans.”

North Korea forced Kim Dong-chul to make a televised confession in which he said he formerly ran a trading and hotel business in the Rason special economic zone near North Korea’s borders with China and Russia.

In the forced confession, he said he began working for “South Korean conservative elements” in 2013 by bribing North Koreans to provide secret information about Pyongyang’s military plans and nuclear weapons program.

“You could say my anti-North Korean behavior was also instigated by the United States,” he added. He made similar statements in an interview with CNN under the watchful eyes of North Korean guards.

The UK Mirror quoted an April 30 interview with Choi Sung-ryong, a “representative of the three prisoners,” who said all three were subjected to hard labor during their captivity and were given “ideological education” and “health treatment” before they were released to the United States.