Many readers have short memories, so there was probably some curiosity over why The Age gave such prominence on Saturday to a story about a hitherto-suppressed United Nations report on Rwanda by an Australian former war crimes investigator.

But the Rwandan genocide of 1994 was one of the most shocking episodes of the century. More than half a million people were massacred in the space of about three months – not by modern industrial methods, but by rifles, grenades and machetes. Equally shocking was the international community’s failure to intervene.

The touchstone for the genocide was the death in a plane crash of Rwanda’s then president, Hutu leader Juvenal Habyarimana. Hutu extremists responded with a well-planned attack on the minority Tutsi community, which only ended when Tutsi forces succeeded in overthrowing the Hutu government, ultimately installing Tutsi leader Paul Kagame as president.

So the question of who was responsible for Habyarimana’s plane crash is of more than academic interest. Last month a French judge, Jean-Louis Bruguière, stirred up a hornet’s nest when he concluded that Kagame and his associates had been responsible for shooting down the plane. Rwanda promptly broke off diplomatic relations with France, accusing it of siding with the perpetrators of genocide.

French peacekeepers had certainly been prominent in turning a blind eye to the massacres. But now The Age reports that the UN uncovered evidence for the same conclusion about Kagame’s responsibility back in 1997, before ordering the investigation to be shut down.

Even if Habyarimana’s death was a political assassination, no-one suggests that genocide was an appropriate response. The analogy that comes to mind is with the Reichstag fire of 1933, used by Adolf Hitler as an excuse to clamp down on political dissent and ultimately to launch his own horrific massacres.

The Nazis claimed the Reichstag fire was a communist conspiracy. Their opponents claimed that the Nazis had set the fire themselves to provide an excuse for repression. In fact, most historians now accept that the Dutch communist who was executed for the crime was actually guilty, and the Nazis were not responsible.

That doesn’t exonerate Hitler, and if Kagame really had his rival assassinated, it would not justify genocide against his people.

But it would remind us again that the world does not divide neatly into good guys and bad guys.