John Sifton is the Asia advocacy director at Human Rights Watch. The opinions expressed in this commentary are his.

(CNN) The death of Otto Warmbier , a 22-year-old student from Ohio imprisoned in North Korea since last year, should be a wake-up call to the international community. Warmbier, who was arrested in January 2016 after attempting to remove a political banner from his hotel, was subject to a show trial and sentenced to 15 years forced labor.

There is, sadly, nothing unusual about the Warmbier case in the abstract. North Korea citizens are regularly subjected to arrest for trifling crimes and sentenced to labor camps. As documented in harrowing detail by a recent UN report , many die in prison from beatings, malnourishment, or untreated sickness, among other causes.

What was strange about North Korea's treatment of Warmbier was that it was meted out to a foreigner. The United States and its allies strongly objected to his arrest, and Warmbier pleaded for forgiveness at his trial, citing what he called the "worst mistake of my life." Most observers expected that after a period of isolation and interrogation, coupled with private diplomacy, Warmbier would be repatriated. That is what has happened with many Americans in the past.

Instead, Warmbier was soon subjected to some unknown kind of mistreatment or possibly brutality, and ended up in a coma — in which he appears to have languished for more than a year. And now, days after returning home, he is dead

The North Korean government's explanation of his death, involving botulism and a misprescribed sleeping pill, is questionable . How did a healthy young man suffer such severe brain damage from a treatable illness? And if he fell into a coma in March 2016, why did the regime not say anything about it — even to Sweden , which usually acts as intermediary with US prisoners — until recently? It is not clear what exactly happened to Warmbier, but it is possible that Warmbier suffered some of the kinds of abuses that befall North Koreans imprisoned in the regime's archipelago of prisoner camps.

The North Korean government won't own up to its problematic record. For decades, it has refused to cooperate in good faith with UN mechanisms set up to address human rights issues, and it still routinely releases absurdly hyperbolic panegyrics and paens to their "Supreme Leader," Kim Jong Un.

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In dealing with North Korea, the international community has historically focused on nonproliferation concerns, but in recent years North Korea's human rights record has been getting more scrutiny . Since 2014, the UN Security Council has even held debates about whether the situation in North Korea should be referred to the International Criminal Court. And the US Congress has passed legislation to tighten bilateral sanctions on North Korea — not just in relation to their weapons program but also to address human rights abuses.

Last December, for the first time, the US Treasury and State Departments specifically sanctioned several senior officials for complicity in human rights abuses (not just for weapons proliferation), including Kim Jong Un himself. Currently, another newer set of names of North Korean officials is being considered by the Treasury Department for listing based on human rights grounds. In the wake of Warmbier's death, the US government should add those names to their list imposing travel and financial services restrictions.

At the United Nations, the US ambassador to the Security Council, Nikki Haley, needs to press other UN member countries to adopt tougher sanctions on human rights and better enforce the ones that already exist. It is often assumed that North Korea is already heavily sanctioned and under a tight embargo. The truth is that what UN sanctions exist are entirely based in the nuclear proliferation context, and although the United States has pushed allies recently to better enforce them, they are weaker than most people realize, and often go unenforced.

What's needed now are sanctions that are more specifically geared toward addressing human rights abuses and raising the cost of doing business for North Korean officials whose business is human rights abuses, like officials in the Ministry of Public Security, and prison wardens and other police officials.

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It is impossible to know what North Korea's future holds, but one hope in the near term is to impose consequences on those responsible for the brutal treatment of prisoners like Warmbier, and the hundreds of thousands of others in North Korea's gulags.

This could create a shadow of fear in officials' minds about possible criminal liability in the future, and reduce the chances of others facing abuses like Otto Warmbier.