Theoneste Bagosora, a former Rwandan army colonel regarded as the architect of the 1994 genocide in which more than 800,000 ethnic Tutsi and Hutus who tried to protect them were killed, died in a hospital in Mali on Saturday.
The 80-year-old Bagosora was serving a 35-year sentence after being found guilty of crimes against humanity by the then-International Criminal Tribunal for Rwanda.
Known as a hardliner within the party of Rwandan President Juvenal Habyarimana, Bagosora was appointed cabinet director in the defense ministry in 1993 and took control of military and political affairs in the country.
Bagosora was accused of taking over the affairs of state after Habyarimana was killed when his plane was shot down in 1994 and ordering the massacre of Tutsi.
After the genocide, Bagosora fled into exile in Cameroon. He was arrested there in 1996 and flown to face trial in Tanzania in 1997.
His trial began in 2002 and lasted until 2007.
Bagosora was sentenced to life in prison in 2008 but that sentence was reduced on appeal.