Washington (CNN) A federal judge in Washington awarded the parents of Otto Warmbier more than half a billion dollars in a wrongful death suit against the North Korean government, which detained and allegedly tortured the college student over 17 months before returning him to the US last year, where he died days later.

In an opinion issued on Christmas Eve, District Judge Beryl A. Howell quoted emotional lines of testimony from Warmbier's mother and recounted grim details of his treatment in North Korea that underpinned the judgment.

"An American family, the Warmbiers, experienced North Korea's brutality first-hand when North Korea seized their son to use as a pawn in that totalitarian state's global shenanigans and face-off with the United States," Howell wrote.

North Korean officials detained Warmbier in 2016 as he tried to leave the country after spending five days there on a commercial tour. Warmbier, then a student at the University of Virginia, was accused by the government of stealing a political poster from a restricted floor in his hotel.

Warmbier returned to the United States in June of 2017 after negotiations led by the Trump administration. Then 22 years old, Warmbier was blind and deaf and had sustained severe brain damage from his time in detention. He died less than a week later in his hometown of Cincinnati.

In a statement Monday, Fred and Cindy Warmbier thanked Howell and called the decision a "significant step on our journey."

"We are thankful that the United States has a fair and open judicial system so that the world can see that the Kim regime is legally and morally responsible for Otto's death. We put ourselves and our family through the ordeal of a lawsuit and public trial because we promised Otto that we will never rest until we have justice for him," they said in the statement.

"As a family, mother, father, sister and brother, we would like to thank all those who knew and loved Otto, and for all those who supported us and our mission to hold Kim liable for his actions," they said, referring to North Korean leader Kim Jong Un.

The damages awarded to the Warmbiers included $45 million for pain, suffering and grief, and more than $6 million in economic losses that Otto Warmbier would have earned in life based on his exceptional talent, according to an economist's model.

Howell wrote in her opinion that the Warmbiers had established "ample evidence" that the damages requested in their suit, which was brought under the Foreign Sovereign Immunities Act in April, met statutory requirements because they arose from "North Korea's barbaric mistreatment of Otto, including 'torture,' 'hostage taking,' and 'extrajudicial killing.' "

A North Korean Foreign Ministry spokesman denied that Warmbier had been tortured while in North Korean custody, according to a 2017 report by the country's state-run news agency KCNA.

Howell's ruling does not guarantee an immediate windfall for the Warmbiers, however.

North Korea did not respond to the lawsuit -- Howell's opinion was rendered as a so-called "default judgment" -- and the country has no free assets in the US that the family could make a claim for.

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Any damages eventually won by the Warmbiers would likely come from North Korea's frozen US assets, which amounted to about $63 million in 2017, according to the Treasury Department's Terrorist Assets Report, and those potential payments would be limited to the compensatory damages in Howell's opinion -- a narrow portion of their larger award.

Requests for comment sent to North Korean officials in New York were not answered.

Steven Perles, an attorney who has won billion-dollar Foreign Soverign Immunities Act judgments for victims of terror attacks, said these cases are brought not for the money, but for the "deterrent value."

"It's not about enriching the Warmbiers here. Nothing can bring their son back, nothing can compensate them," Perles said. "But if they can really take money away from the North Koreans, maybe the North Koreans or some other would-be bad actor would think twice before doing this to somebody else. That's the only reason you do this."

A few hours after Howell's opinion was published, President Donald Trump said Monday afternoon that he had been briefed by his team working on North Korea and he was looking forward to a second summit with Kim. He made no mention of the judgment.

"Christmas Eve briefing with my team working on North Korea -- Progress being made. Looking forward to my next summit with Chairman Kim!" Trump said on Twitter.