My friend nervously scanned the paved open-air courtyard. His eyes rested for a few seconds on a nearby table, where three affluent-looking men in suits sipped beers. He glanced into a shadowed corner at a young couple out on a date, then at a group of foreign missionaries gathering for an early dinner.

Dusk had just passed the way it does in equatorial Africa, suddenly, leaving us in darkness as waiters scurried about with matches to light candles. Satisfied that no one was listening in, my friend leaned close to whisper, “Of course, everyone knows who is Hutu, who is Tutsi. We just don’t talk about it. We can’t talk about it.”

There are many things you cannot talk about in Rwanda. You cannot talk about ethnicity because this little central African country was nearly destroyed by tribal enmities just sixteen years ago, when extremist Hutus killed around 800,000 Tutsis and moderate members of their own tribe in just three months. The killers used machetes, hoes, axes and guns to perpetrate one of the most efficient mass slaughters in human history.

Paul Kagame, the country’s de facto leader since marching into Rwanda at the head of a Tutsi rebel army in the summer of 1994, calls himself a Rwandan. The words “Tutsi” and “Hutu” have been erased from identity cards and excised from open conversation. But still, everyone knows.

There are laws against “divisionism” and “genocide ideology” that prescribe jail terms for tribal talk. One Western diplomat in Kigali told me these were “thought crimes.” The laws are intended to prevent the resurrection of deadly ethnic politics, but it is also a very pragmatic concern for Kagame, whose Tutsi ethnic group accounts for only around 15 percent of Rwanda’s 10 million citizens. Critics complain that the laws are used to block opposition politicians and stifle dissent.

There are two things you can—indeed must—talk about in Rwanda. The first is the genocide. Seemingly every town has its own genocide memorial, mausoleums with neatly arranged rows of skulls and bones on wooden shelves. They are eerie places, and impossibly moving. The second is that Kagame and his troops halted the genocide and have shown a single-minded determination to rebuild the country ever since.

Last month a draft United Nations report was leaked that questions this dominant discourse, forcing Rwandans to confront something else that cannot be talked about in Rwanda: what happened in neighboring Democratic Republic of Congo after the genocide?

For seven months a team of researchers from the UN’s Geneva-based Office of the High Commissioner for Human Rights consulted documents (more than 1,500 of them) and interviewed witnesses (over 1,200) across Congo’s vast territory. They concluded that Kagame’s own troops were responsible for a litany of atrocities and massacres after the Rwanda genocide was over. Some journalists, human rights activists and others have long argued that Rwanda’s invasion was a “counter-genocide,” but never have the allegations been leveled in such detail, and by an international body like the UN.

As Kagame’s army advanced southward through Rwanda in 1994, the Hutu killers fled to neighboring Congo, hiding among more than a million refugees in squalid camps along the border. From there the genocidaires reorganized, rearmed and restarted cross-border attacks on Tutsis. In 1996 Kagame ordered an invasion to hunt down the killers.

The UN researchers were tasked with documenting the most serious violations of human rights committed in Congo during a series of wars between 1993 and 2003, which, at their height, involved eight countries and led to the deaths of around 4 million people, mostly from disease and ill health.

The draft report talks of “the relentless pursuit and mass killing of Hutu refugees, members of the former Armed Forces of Rwanda and militias implicated in the genocide of 1994.” Revenge attacks might be understandable, given the horrific context of the genocide; but the authors of the report believe a baser motivation may have been in play.

“The systematic and widespread attacks…reveal a number of damning elements that, if proven before a competent court, could be classified as crimes of genocide,” the draft says. “Probably tens of thousands were killed” as Rwandan soldiers made “no effort” to distinguish between combatants and civilians. So many deaths “cannot be attributed to the hazards of war or seen as equating to collateral damage,” says the report. “The majority of the victims were children, women, elderly people and the sick, who were often undernourished and posed no threat to the attacking forces.”

One example, from 1996: It was a Wednesday afternoon in October, the day before Halloween, when a meeting was ordered in Rutshuru, a town set among the cultivated hills and forested mountains of eastern Congo. The Rwandan soldiers who had fought their way to Rutshuru four days earlier began registering people according to tribe. Nandes were told to go home, Hutus to stay.

“They then separated the men and women on the grounds that the women had to prepare the meal. The women were taken to the Maison de Poste, where they were executed. The men were bound and led in pairs to a sand quarry…. All of them were then executed with blows of hammers [sic].”

The death toll that day alone was “at least 350 civilians,” according to the draft report. This incident was just one of 617 listed by the researchers. Of these, one in six were carried out by Rwandan soldiers and their allies (the other killings were by various warring parties from eight countries that were embroiled in the Congo fighting).

It is damning, and Rwanda’s government has reacted angrily, dismissing the report as “immoral and unacceptable.” Even before the draft was leaked, Rwanda’s foreign minister wrote a letter to UN Secretary General Ban Ki-moon threatening to withdraw the country’s soldiers from UN peacekeeping missions if the report was published, or leaked, in its current form. Rwanda’s 3,300 troops are the backbone of a hard-pressed UN and African Union mission in the Sudanese region of Darfur, so on September 8, Ban paid a surprise visit to Rwanda to plead with Kagame not to follow through on the threat.

The leaked report is hugely damaging to Kagame’s moral authority and international standing, all of which stem from his ending of the Rwanda genocide, not attempting a second one in Congo.

Already Kagame has had a torrid year, during which he has faced unprecedented scrutiny. He won a presidential election in August with 93 percent of the vote, but two opposition candidates were prevented from registering their parties for the poll, critical newspapers were shut down and the mysterious murders of a journalist and politician as well as the attempted assassination of a dissident general did immense damage to Kagame’s well-cultivated image as Rwanda’s savior and visionary leader.

A decade and a half since that massacre in Rutshuru, eastern Congo is still at war, albeit a low-intensity conflict that harms more civilians than soldiers. The provincial capital of Goma is no longer engulfed by refugees, but there is an almost constant trickle of what aid workers call the displaced, those forced from their homes by violence.

Dreadful things are done every day despite the presence of one of the world’s largest UN peacekeeping missions. A senior UN official recently conceded the mission had “failed” to protect civilians when he admitted that more than 500 women and girls had been raped in just over a month of attacks.

The picture in neighboring Rwanda could scarcely be more different. It is a short walk from Goma in Congo to Gisenyi in Rwanda, but it takes you from chaos to discipline, from conflict to peace. Since taking charge, Kagame has effectively leveraged the guilt felt by Western powers who turned their backs on Rwanda during the 1994 genocide. He has attracted vast amounts of aid and has used the money well.

The corruption, bribes and backhanders that blight Rwanda’s neighbors are hard to find. Schools have been built and teachers trained; children get nine years of free education; a national health insurance scheme has been set up; a network of fiber optic cables is being laid; and the economy has grown impressively, albeit from a very low base.

Post-genocide reconciliation is a slow but ongoing process, and Rwanda is both peaceful and safe. Crime is rare, violent crime almost unheard of.

But the leaked UN report points to a darker side of Kagame’s Rwanda, a place where people are afraid to criticize the government, where central control is grasped tightly, where everything is creepily disciplined.

“Rwandans are characterized by obeying the government,” says Irenee Bugingo, a researcher at Kigali’s Institute of Research and Dialogue for Peace, which works to foster reconciliation. He says this can be used for good—for example, during the last Saturday in each month, when everyone gets involved in a morning’s worth of community work, called umuganda—or it can be used for ill, as in 1994, when extremist leaders ordered Hutus to turn on their Tutsi neighbors.

Kagame has brought a military discipline to the governing of Rwanda, but with it comes a soldier’s ruthlessness and intolerance of dissent. It is not just ordinary Rwandans like my friend who are afraid to talk openly. Foreign diplomats and aid workers in Kigali are guarded when they speak on the telephone for fear of tapping; in their embassies and offices, they speak more quietly as local staff pass by.

“The country is obsessively controlled, the regime profoundly paranoid,” one Western diplomat told me. “Fear is the dominant expression among ordinary people,” said another.

Kagame’s control of the country has maintained stability in the years since the genocide and fostered a measure of economic growth and prosperity, but there are doubts over how sustainable it will be in the longer term, argues Carina Tertsakian, a senior researcher with Human Rights Watch.

“People may shut up and do as they’re told, but inside they are increasingly bitter and frustrated, and that cuts right across ethnic lines,” she says. “You can’t build stability, peace, reconciliation, in a society where people can’t speak.”