Fred and Cindy Warmbier filed a claim for ownership of a North Korean coal ship seized by the United States. The couple says it wants North Korea to fulfill the $500 million default judgment a court awarded for the death of their son Otto Warmbier. (Maddie McGarvey for The Washington Post)

Otto Warmbier’s parents have filed a claim for a North Korean cargo ship in an attempt to force the country to pay part of a $500 million court judgment in the death of their son.

The move is another step in Fred and Cindy Warmbier’s fight to get justice as North Korea’s handling of their son’s case becomes a flash point in the broader geopolitical drama playing out between the United States and Kim Jong Un’s regime.

The Warmbiers are asserting ownership of the vessel that U.S. authorities seized in May over allegations that the ship had been used to sell coal in violation of international sanctions, according to a federal lawsuit filed in New York.

The Justice Department has said the 17,601-ton bulk carrier ship, the Wise Honest, was approaching U.S. territorial waters in American Samoa last year when Indonesian officials took it out of service. U.S. authorities say the ship, now in their possession, was among a fleet transporting coal from North Korea and returning with heavy machinery, disregarding U.S. and U.N. sanctions.

North Korea has refused to abide by the federal court judgment against it, the Warmbiers wrote in their lawsuit, so the couple are seeking North Korean assets to recover what they can for the loss of their son, a University of Virginia student.

“We are committed to holding North Korea accountable for the death of our son, Otto, and will work tirelessly to seize North Korean assets wherever they may be found,” the Warmbiers said in a statement.

Otto Warmbier, then 21, was arrested by North Korean officials during what was supposed to be a five-day visit with a tour group. He was convicted on charges related to tearing down a propaganda sign in a Pyongyang hotel — an offense the regime considered a “hostile act against the state” and Warmbier called “the worst mistake of my life” at a highly orchestrated news conference.

Warmbier, an Ohio native, was sentenced in March 2016 to 15 years of hard labor in prison. He became comatose that night and was held by North Korea for 15 more months before the government sent him back to the United States in a vegetative state. He never regained consciousness and died six days later.

The cause of Warmbier’s coma has never been established: The parents allege it was a result of torture, while the Kim regime maintains it was caused by botulism and sleeping pills. A coroner in Hamilton County, Ohio, determined Warmbier suffered a lack of oxygen flow to his brain.

There’s evil in this world,” Cindy Warmbier told a federal judge in December. “It’s North Korea.”

Chief Judge Beryl A. Howell of the U.S. District Court for the District of Columbia ruled the multimillion-dollar judgment against North Korea was necessary to punish the regime for Warmbier’s “torture, hostage-taking, and extrajudicial killing.” He had been a healthy, smart and socially successful college junior when he entered North Korea, Howell wrote, and blind, deaf and brain dead when he returned home.

Although foreign nations are usually immune from lawsuits in the United States, Howell said an exception for terrorism applied to Warmbier’s case. North Korea never responded to the lawsuit, and the judge deemed the nation legally in default.

Howell agreed with the Warmbiers’ lawyers that their son had been used as leverage in North Korea’s confrontation with the United States involving nuclear testing and economic sanctions. Experts previously told The Washington Post the judgment would be difficult or impossible to enforce.

President Trump this year has pointed to Warmbier as an example of North Korea’s brutality to stir up public sympathy as the United States conducts nuclear negotiations with Kim’s regime. Trump, however, said in February that he believed Kim, himself, did not know about Warmbier’s case as it played out and that the dictator “feels badly about it.”

“He tells me he didn’t know about it, and I take him at his word,” Trump said at a news conference in Hanoi.

The Warmbiers responded with a sharp statement asserting that “Kim and his evil regime are responsible for unimaginable cruelty and inhumanity.” The remarks were a sign of the family’s frustration with Trump’s embrace of Kim, which recently included stepping over the military demarcation line between the Koreas and becoming the first sitting U.S. president to set foot in North Korea.

Read more:

Iran is prepared to enrich uranium beyond limits set by nuclear accord, senior official says

CBP officials knew about derogatory Facebook group and have investigated posts

Sudan may follow a perilous Arab Spring playbook: The strongman falls, his allies remain

An Indonesian woman recorded lewd calls from her boss. Now she’s going to jail while he walks free.