The parents of Otto Warmbier, a college student who died after spending more than a year in North Korean custody, have sued the East Asian country's regime, accusing them of torture and mistreatment. Cynthia and Fred Warmbier filed a lawsuit Thursday in the U.S. District Court of Washington, D.C., in which they said North Korea “ brutally  tortured and murdered” their 22-year-old son.

“Otto was taken hostage, kept as a prisoner for political purposes, used as a pawn and subjected to exceptionally harsh and brutal treatment by the North Korean regime.” his father said in a statement.

Otto, from Cincinnati, Ohio, was arrested at Pyongyang airport in January 2016 and was sentenced to 15 years in prison, as punishment for taking a poster from his hotel room where he had been staying during an organized tour. He was released, however, on Jun. 13, 2017, when he returned to the United States in a state of coma. Otto returned to his home town where his parents were informed he had suffered from brain damage. He died after few days and medical authorities said the cause of death was lack of oxygen and blood to the brain.

The North Korean regime blamed botulism (which refers to food poisoning caused by bacterial growth in preserved foods) and ingestion of sleeping pills for the cause of his death. However, the medical practitioners in Ohio who examined his body said they found no sign of botulism.

Otto Warmbier The casket of Otto Warmbier is carried out from his funeral at Wyoming High School in Wyoming, Ohio, June 22, 2017. Photo: Getty images/Bill Pugliano

The timing of the lawsuit is significant, since it was filed just weeks before President Donald Trump is scheduled to meet with North Korean leader Kim Jong Un. It also comes just days after the Trump administration announced that former director of CIA and now Secretary of State Mike Pompeo met with Kim recently in an effort to lay the foundation for direct talks between Trump and Kim.

When Otto was brought to United States in a vegetative state, Trump condoned the barbaric and inhumane treatment meted out by North Korean regime. In a statement, he said: “Otto’s fate deepens my administration’s determination to prevent such tragedies from befalling innocent people at the hands of regimes that do not respect the law or basic human decency.”

In the wake of this incident, the government issued a permanent ban on Americans from traveling to North Korea.

The lawsuit filed by Otto’s parents is not the first lawsuit filed against the North Korean regime, several U.S. citizens  in the past sued the regime and won default judgments after Pyongyang declined to show up for the cases.