Alison Des Forges, 66, Human Rights Advocate, Dies

The MacArthur Foundation recognized her work with a $375,000 “genius” grant in 1999. Her authoritative book, “Leave None to Tell the Story: Genocide in Rwanda,” was published that year.

On its Web site, the United States Holocaust Memorial Museum said Dr. Des Forges’ book provides “a meticulously detailed description of the organization of the campaign that killed some half million Tutsi,” adding that it “analyzes the failure of the international community to intervene in the genocide.”

Mahmood Mamdani, a professor of government and anthropology at Columbia University and the author of the book “When Victims Become Killers: Colonialism, Nativism and Genocide in Rwanda” (2001), called Dr. Des Forges “the leading person who sought to document the events leading up to the Rwandan genocide, so that future generations would have the material on hand to draw the appropriate lessons from it.”

In 2001, after a Belgian court sentenced four Rwandans, two of them Roman Catholic nuns, to long prison terms for their roles in the genocide, Dr. Des Forges said she had been deeply impressed by the proceedings — the first in which a jury of ordinary citizens was asked to sit in judgment of war crimes in another nation.

“People maybe don’t even realize just how revolutionary this jury trial, so far from the events, really is,” she told The Times then. The Belgian trial, she said, “has been done with a great deal more depth than those in Rwanda.”

Dr. Des Forges was also an authority on human rights violations in Burundi and the Democratic Republic of Congo, formerly Zaire.

While a central focus of her work was documenting the crimes of the Hutu-led government that organized the three-month-long genocide, Dr. Des Forges later leveled strong criticism of the Rwandan Patriotic Front, the Tutsi-led rebel movement headed by Paul Kagame, now Rwanda’s president. His government has been in power since the genocide.