Habré consolidated his dictatorship through a power system that relied on corruption and violence with thousands of people estimated to have been killed under his rule. The president favoured his own Toubou ethnic group and discriminated against his former allies, the Zaghawa. His general, Idriss Déby, overthrew him in 1990. Attempts to prosecute Habré led to his placement under house arrest in Senegal in 2005; in 2013, Habré was formally charged with war crimes committed during his rule. In May 2016, he was found guilty of human-rights abuses, including rape, sexual slavery, and ordering the killing of 40,000 people, and sentenced to life in prison.