Patrick Karegeya: Mysterious death of a Rwandan exile
27 March 2014 Last updated at 15:29 GMT
A murdered former Rwandan intelligence chief had been advising South African and Tanzanian intelligence as they prepared to send troops to the Democratic Republic of Congo to battle the Rwandan-backed rebel group M23, the BBC has learned.
On New Year's Eve, Rwanda's former chief of external intelligence, Col Patrick Karegeya, was killed after going to his hotel suite in Johannesburg's business district to meet an old informant, who is believed to have been used as bait.
Col Karegeya was once one of the most powerful figures in Rwanda. He fled to South Africa in 2008, after falling out with the regime. There he helped set up an opposition movement, the Rwandan National Congress.
His friends and family are in no doubt that he was murdered on the orders of the Rwandan president. Gabriel Gatehouse reports for BBC Newsnight.