A Senegal tribunal investigating alleged atrocities committed by exiled former Chadian President Hissene Habre opened on Friday, leading the way for the first trial of an ex-head of state by another country for rights abuses.
Prosecutors will work at a sea-front court in the Senegalese capital Dakar, investigating the alleged killing and torture of 40,000 people during Habre's 1982-1990 rule.
Habre, 70, is accused of using his feared secret police, the Documentation and Security Directorate (DDS), to target political opponents and rival ethnic groups after seizing power in a military coup in the landlocked central African state.
For the last 22 years, he has lived in exile in Senegal after being toppled by current Chadian President Idriss Deby.
"I am overcome by emotion," Clement Abaifouta, president of the Chadian victims' association, told journalists at the opening of the court. "For four years, languishing in Habre's jails, I saw the worst at the hands of the DDS. This is a bright day."
Files found at the abandoned headquarters of the DDS detailed how they forced prisoners mouths around cars' exhaust pipes or made victims drink water until they lost consciousness to extract confessions, according to Human Rights Watch.
Reed Brody, legal counsel for Human Rights Watch, said that the long-delayed opening of the tribunal - more than a decade after Habre was first detained in Senegal - sent "a powerful message to leaders in Africa and elsewhere that if they commit atrocity crimes against their own people, they could also be brought to justice one day".
The inquiry, which will draw on extensive evidence collected by international human rights organisations and prosecutors in Belgium, is expected to last at least 15 months, lawyers said.
A trial, presided over by an African Union-appointed judge, could take a further seven months, said Jacqueline Moudeina, a lawyer for Habre's victims.
International frustration had mounted over Senegal's failure to prosecute Habre, a once-wealthy man who had influential friends. The previous Senegalese government had said at first it did not have the jurisdiction to hold a trial. Once laws were changed, it said it lacked the funds.
The International Court of Justice had ordered Dakar in July to try Habre or extradite him to Belgium, which has laws allowing the prosecution of international human rights crimes.
But the long-delayed prosecution was kick-started by a change of government in Senegal after the victory of Macky Sall in April's presidential election and the appointment of his forceful Justice Minister Aminata Toure.
Africa has a human rights court which sits in Arusha, Tanzania, but its status has only been ratified by 26 countries.
Former African heads of state have stood trial before, but only in their own countries or before international tribunals, never in the court of another country.
Jean-Bedel Bokassa, the self-proclaimed Emperor of Central African Republic, was convicted of treason and murder after his 13-rule ended in a coup in 1979.
Bokassa, who was cleared of charges of cannibalism, was jailed for life but served only six years.