Archbishop Emeritus Desmond Tutu is fronting an appeal by hundreds of human rights activists in urging Senegal to try the exiled Chadian dictator Hissene Habre for mass murder and torture.
A signed Human Rights Watch appeal to the Senegalese government and the African Union is calling for the long-delayed trial of Habre to begin, following 10 years exile in Dakar.
The case has been dragging on since Habre was first indicted in Senegal in 2000.
If the dictator went on trial in his own country it would be a historical precedent for Africa.
Human Rights Watch (HRW) says Habre's "one-party regime was marked by widespread atrocities, including waves of ethnic campaigns."
"Files of Habre's political police reveal the names of 1,208 people who were killed or died in detention," HRW declares. "A total of 12,321 victims of human rights violations were mentioned in the files."
After the initial indictment, Senegal said that it had no jurisdiction to try the case and he was later charged by Belgium with crimes against humanity, war crimes, and torture.
Senegal rejected a Belgian extradition request, and the African Union charged Senegal with putting Habre on trial. But it has been delayed by Senegal disputing the trial budget with international funders.
The petition says: "We, the undersigned NGOs and individuals urge Senegal rapidly to begin legal proceedings against the exiled former Chadian dictator Hissene Habre, who is accused of thousands of political killings and systematic torture from 1982 to 1990."
The document has been released by Human Rights Watch ahead of an African summit in Kampala next week.
Other signatories of the petition include 117 African rights groups from 25 countries and prominent individuals such as South Africa's Richard Goldstone.
Mr Goldstone was first prosecutor of the UN war crimes tribunals for the former Yugoslavia and for Rwanda, and more recently headed the Gaza fact-finding commission which called for concerted action from Israel.