The parents of U.S. college student Otto Warmbier filed a wrongful death lawsuit against North Korea on Thursday, saying its government tortured and killed their son.

Fred and Cindy Warmbier filed the lawsuit in the U.S. District Court in Washington, D.C., seeking compensation for the death of the 22-year-old, whose plight had compounded tense U.S.-North Korean relations.

Otto Warmbier, who was a student at University of Virginia, was arrested by North Korean authorities in January 2016 for stealing a propaganda poster and sentenced to 15 years in prison with hard labor. He died in June 2017, days after he was repatriated to the U.S. with severe brain damage.

While the lawsuit may prove largely symbolic given the difficulty of recovering any damages the court might order, it comes at a delicate time in relations between Washington and Pyongyang. President Donald Trump is planning an unprecedented summit with North Korean leader Kim Jong Un in the coming weeks to address the threat posed by its nuclear weapons, and the leaders of North and South Korea are due to meet Friday.

“Otto was taken hostage, kept as a prisoner for political purposes, used as a pawn and singled out for exceptionally harsh and brutal treatment by Kim Jong Un,” Fred Warmbier said in a statement.

“Kim and his regime have portrayed themselves as innocent, while they intentionally destroyed our son’s life. This lawsuit is another step in holding North Korea accountable for its barbaric treatment of Otto and our family,” he said.

The 22-page complaint outlines in blunt terms the adverse fortunes of Warmbier after he went on a five-day tour to North Korea run by a China-based tour operator, prior to taking up a study program in Hong Kong. He sought get a better understanding how people in the North’s closed society lived, the lawsuit says.

It says that after his arrest, Warmbier, from Cincinnati, Ohio, was pressured to make a televised confession and then convicted of subversion after a one-hour trial. He was denied communication with his family by any means until in early June 2017 they were informed he was in a coma and had been in that condition for one year.

The lawsuit says that when Warmbier returned, his parents “were stunned to see his condition. Otto was blind and deaf. He had a shaved head, a feeding tube coming out of his nose, was jerking violently and howling, and was completely unresponsive to any of their efforts to comfort him.” His once straight teeth were misaligned and he had an unexplained, scarred wound on his left foot.

North Korea claimed that Warmbier had contracted botulism but his physicians in the U.S. found no evidence of that, according to the lawsuit which says that the North’s false explanations for Otto’s condition demonstrate that is it “covering up its torture and mistreatment of Otto while he was in North Korean custody.”

The lawsuit contends that North Korea is liable for Warmbier’s wrongful death — describing it as “extrajudicial killing” — and calls for a judgment for both “economic and non-economic compensatory damages” to his parents.

North Korea’s mission at the United Nations in New York did not immediately respond Thursday to emails and phone calls seeking comment about the lawsuit.

There are still three Americans held in North Korea, and their cases are a continuing source of tense relations between the adversary nations. U.S. officials have said that Mike Pompeo, the outgoing CIA director, raised the issue when he met with Kim on a rare trip to North Korea nearly four weeks ago to prepare for a Trump-Kim summit.

(AP)