Rwandan opposition political leader Seif Bamporiki was shot dead in South Africa, where he was living in exile.
Mr. Bamporiki was pulled from his vehicle in a Cape Town municipality before being killed, police said.
Preliminary investigations have shown that he was killed in a robbery, police said. But Mr. Bamporiki’s party, the Rwanda National Congress (RNC), said the motive was still unclear.
Rwanda has previously been accused of targeting dissidents in South Africa.
He has always denied the allegation.
The RNC was formed in exile by opposition politicians who accuse President Paul Kagame’s government of being authoritarian and of not tolerating dissent.
Mr. Bamporiki operated a bedding shop in Cape Town. He was making a delivery Sunday in Nyanga township when he was shot dead after being confronted by two men, police said.
“The deceased was pulled from his vehicle and shot dead while the 50-year-old man accompanying him escaped unharmed.
“The suspects yet to be arrested fled with the deceased’s vehicle, and we have reason to believe the motive for the murder was theft,” police added in a statement to the BBC.
RNC spokesman Etienne Mutabazi gave a different account, claiming that Mr. Bamporiki was killed after an armed man fired a single shot through the car window.
There was speculation on social media that Mr Bamporiki was killed in a political coup, but Mr Mutabazi said he did not know if this was the case, reports BBC’s Namesa Maseko from the main town South Africa, Johannesburg.
Nyanga is known to be one of the most dangerous towns in South Africa, with a high crime rate, she adds.
Former Rwandan intelligence chief and founding member of the RNC, Patrick Karegeya, was assassinated in a hotel room in Johannesburg in 2014.
Another founding member of the RNC, former army chief General Faustin Nyamwasa, was shot and wounded in Johannesburg in 2010.
The attacks sparked a huge diplomatic row between South Africa and Rwanda in 2014.
South Africa has expelled three Rwandan diplomats after accusing them of links to the murder and attempted murder of Rwandan dissidents living in the country.
The Rwandan government has rejected this allegation.