Ashley S. Kinseth is an international human rights lawyer and founder of the nonprofit organization Stateless Dignity Project, which works to advocate for and advance the rights, safety and human dignity of stateless persons.

One year ago, a small group of Rohingya militants attacked security forces in western Myanmar. The attacks by the insurgents left 12 troops dead — a regrettable tragedy in its own right. But what happened next would pale in comparison.

Within the next few weeks, the Myanmar military launched a full-scale campaign of violence and terror against the Rohingya Muslim minority population in Rakhine state. The soldiers set homes ablaze, massacred thousands of civilians and in many cases even deployed rape as a weapon of war. The Rohingya — almost entirely unarmed — responded the only way they could: by running away. By the end of 2017, some 800,000 of them had fled across the border into neighboring Bangladesh, where they remain today, too terrified to return.

The Myanmar government has its own version of these events. The story essentially goes like this: The armed forces in the region were going about their usual task of maintaining the peace when they were treacherously attacked by a well-armed network of Rohingya insurgents. Caught entirely off guard, the military then launched a purely defensive counterterrorism operation aimed at rooting out the terrorists. In the course of that campaign, Myanmar maintains, local Rohingya burned down their own homes and faked evidence of atrocities against themselves in order to vilify the troops and turn world opinion against the government.

As you might have guessed by now, there’s just one problem with this story: It isn’t true.

Over the past year, a number of independent observers have accumulated overwhelming evidence that the assault on the Rohingya was fully premeditated, an “orchestrated campaign” carefully planned in advance. In September, in the midst of the operation, Myanmar military chief Min Aung Hlaing publicly referred to the embattled Rohingya as a “problem,” “a long-standing one which has become an unfinished job” — a job, it seems, that he and his fellow officers were determined to complete once and for all.

Why is this important? Because human rights law treats premeditation as a crucial element in the definition of genocide — a word that even usually cautious United Nations officials soon found themselves using as the campaign proceeded throughout the fall of 2017.

As a human rights lawyer who has spent years working in Myanmar, I’ve had many occasions to witness firsthand the discrimination and hatred that the Rohingya have long been forced to endure. Even though most of them have lived in Myanmar for generations, members of the overwhelmingly Muslim group have been purposefully vilified by the Myanmar government and other members of the Buddhist majority as illegal immigrants from neighboring Bangladesh. For the past four decades the Myanmar government has denied the Rohingya citizenship, basic civil rights (including freedom of movement) and even the right to choose what they should be called.

Now, it seems, the Myanmar military had decided to “finish” the job of excluding the Rohingya from national life for good. Reuters journalists have since provided one of the most thorough accounts of the military’s advance preparations for its effort to drive the Rohingya out of Myanmar. The reporters obtained evidence that the military had already deployed its most brutal infantry divisions across the region by August 10 — well before the insurgent attacks. The units sent had already earned dark reputations for their ruthless counter-insurgency campaigns against other ethnic minorities. The journalists detailed the disturbingly raw ethnic hatred of the brigades’ troops: “Crush the [Rohingya], buddy,” one soldier’s friend wrote. “Will do,” the soldier replied.

The dramatic military influx “stoked fear and tension across a volatile region,” the journalists noted. In retrospect, it would seem, that was precisely the point.

Around the same time, the authorities had stopped granting foreigners like myself access to villages in more densely Rohingya-populated areas. This contrasted sharply with my work there in 2013, when I and my colleagues had virtually free rein to visit any village in the area. In hindsight, of course, I now realize that this, too, was also evidence of advance planning: officialdom wanted to keep prying eyes away. From our own vantage point in the area we could see and hear signs of the rising military presence — well before the killing started.

Last month, the human rights organization Fortify Rights released a groundbreaking 162-page report, based on interviews with dozens of witnesses, that shows the astonishing extent of Myanmar’s genocidal intentions. The group’s investigators determined that, well in advance of August 25, the Myanmar military had actively trained and armed non-Rohingya civilians to assist in its campaign — all while confiscating from the Rohingya even the most basic of tools (“sharp and blunt objects”) that might be used in self-defense. The report further found that Myanmar blocked critical humanitarian aid to the Rohingya and planted landmines across the region.

Such accounts shatter any lingering illusions of an organically hatched conflict. Legally, they support a key element in proving genocide — that Myanmar acted with intent to decimate the Rohingya.

The international community has yet to come to terms with the full implications of this conclusion. But one thing is clear: Impunity for those responsible cannot be the answer.