The International Criminal Tribunal for Rwanda found Nzabonimana, a former youth minister, guilty of genocide, conspiracy to commit genocide and incitement to commit genocide in Rwanda in 1994, The Guardian reported.
Nzabonimana, an ethnic Hutu, was arrested in Tanzania in February 2008 after the United States offered a $5 million reward for his capture. His conviction and sentencing came down to his participation in a meeting in the central Gitarama province.
"The trial chamber found that on April 14, 1994, at Cyayi center, Nzabonimana instigated the killing of Tutsis taking refuge at the Nyabikenke commune office, and that between 15 and 60 Tutsis were subsequently killed," the court said.
"It also found Nzabonimana guilty of entering into two separate agreements to kill Tutsis in Gitarama prefecture. Nzabonimana entered into an agreement to kill Tutsis with members of the interim government on April 18, 1994, and entered into another agreement with Jean Damascene Ukirikyeyezu to kill Tutsis in May 1994," the court said.
Nzabonimana's attorney said he plans on appealing the life sentence.
"We will definitely appeal. The appeal hearing starts now," lead defense counsel Vincent Courcelle-Labrousse said.
Between April and June 1994, ethnic Hutu militia and soldiers killed 800,000 ethnic Tutsis and politically moderate Hutus in Rwanda. The ICTR is due to complete the prosecution of leaders of the genocide by 2014.
The tribunal's Web site lists 72 completed cases, two in progress and one awaiting trial.