CINCINNATI — A U.S. judge said North Korea must pay the family of Otto Warmbier about $500 million for the 22-year-old's death.

Warmbier died days after being flown back to Cincinnati from North Korea, where he had been imprisoned for 17 months.

His parents, Cindy and Fred Warmbier, filed a wrongful death lawsuit against North Korea in April, saying they wanted to strike a retaliatory blow against North Korean leader Kim Jong Un's repressive regime.

"I'm going to stand up to evil when I see it," Cindy Warmbier previously said. "There's nothing more evil than North Korea."

A federal district court judge in Washington, D.C. ordered on Monday that North Korea pay more than $21 million to Warmbier's estate in compensatory damages and $150 million in punitive damages, as well as pay $15 million in compensatory damages and $150 million in punitive damages to each of Otto's parents.

"North Korea is liable for the torture, hostage taking, and extrajudicial killing of Otto Warmbier, and the injuries to his mother and father, Fred and Cindy Warmbier," Chief Judge Beryl A. Howell wrote in a memorandum opinion.

North Korea did not send a representative to a hearing about the case last week. There is no mechanism in place to force North Korea to pay, the Associated Press reported.

Warmbier was a Cincinnati native and Wyoming High School graduate. He was a student at the University of Virginia when he traveled to North Korea as part of a five-day guided tour. During the visit in early 2016, North Korean authorities alleged that Warmbier stole a propaganda poster. He was sentenced to 15 years of hard labor.

North Korean leaders agreed to release Warmbier in June 2017. But when he was returned home, doctors said he was in a state of "unresponsive wakefullness." North Korean officials claimed Warmbier had contracted botulism and fell into a coma after he was given a sleeping pill, but doctors in the U.S. said there was no evidence of botulism.

Warmbier's parents said that the regime brutally tortured and murdered their son.

“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. 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," said Fred Warmbier in a statement after filing the suit.