South African police say they're making progress in investigating the death of former Rwandan spymaster whose body was found in a plush Johannesburg hotel on New Year's Day.

Members of the Rwandan political opposition say Patrick Karegeya was assassinated at the behest of the Rwandan government.

The special investigation force, the Hawks, say they are making progress in their investigation into what they say is the murder of Karegeya. Police suspect he might have been strangled. His neck was swollen and a rope and bloody towel were found.

The former head of Rwanda's external intelligence service, Karegeya had been living in exile in South Africa for more than five years. No arrests have been made yet in his death.

"We are exploring all avenues," Hawks spokesman Captain Paul Ramaloko said.