A Johannesburg hotel is now a crime scene.
Police there say exiled former Rwandan intelligence chief Patrick Karegeya was found murdered in his room.
Karegeya fled Rwanda in 2007 after allegedly plotting a coup against President Paul Kagame.
A Rwandan opposition party blamed Kagame's government for Keregeya's death, calling it an assassination.
Spokespeople at the Rwandan embassy in Pretoria were not immediately available to comment on the accusation.
Few other details are known.
