It was just a bolt of pink cotton lying on the floor of a school gym but more than 20 years later, it haunts me still – soldiers tore off strips of that cloth, blindfolded dozens of men, trucked them to a nearby field, shot them, and buried all but a handful of survivors in mass graves. Today, the man who presided over the Bosnian Serb Republic as his troops committed mass killings at Srebrenica, was found guilty of genocide and crimes against humanity by the International Criminal Tribunal for the former Yugoslavia and sentenced to 40 years in prison.

Two Bosnian Muslim women cry over a coffin July 10, 2005 with remains of their relative in a factory hall in Potocari where 610 victims of Srebrenica massacre wait for the funeral.

Radovan Karadzic lived in Sarajevo for years but ordered his troops to besiege the city for 44 months; more than 10,000 people were killed by sniper fire and shells. One was Ibrahim Osmic, a 56-year-old shot dead as he shoveled snow near a front-line bridge during a ceasefire after the Markale market massacre in February 1994 prompted NATO to demand an end to the shelling. I saw his body lying in the morgue at Kosevo Hospital, where Karadzic had worked as a psychiatrist.

Nine months after the Srebrenica massacre, when Karadzic’s forces killed more than 7,000 people, I traveled through those killing fields, dazed and horrified to see the evidence all around. Scraps of the same pink cloth tramped into the mud of a mass grave, human bones pushing through the seedling grass. Bullet holes, blood, brains scarring the walls of an agricultural warehouse where a couple of guys were working, trampling over the labels placed around the site by war crimes investigators.

I remember thinking there was no point asking anyone, “What happened here?” because they would just say nothing. But if we asked, “Where were you when they shot all those men?” it was different – then people would say, “Oh I wasn’t here that day, I was away when it happened.”

Karadzic, who defended himself, told the court in The Hague, “They're trying to convict us for something we never did,” and described the siege of Sarajevo as a “myth.”

It took years for the International Criminal Tribunal for the former Yugoslavia to gather and present the evidence of genocide and crimes against humanity. Karadzic, in hiding for more than a decade until his arrest in 2008, has been on trial since 2009.

His conviction brings some comfort to those who survived his many crimes – in Sarajevo, Srebrenica, and beyond. Above all, I hope that future warlords are taking note: justice will come one day.