Friends and relatives of John Williams Ntwali have called for an independent international investigation into his death in the Rwandan capital, Kigali.
Police say Mr Ntwali – one of the last independent journalists in the central African nation – had died in a road accident.
But he hadn’t been seen since reporting to a police station on Tuesday.
His family were only notified of the death on Thursday.
Several critics of President Paul Kagame have died in suspicious circumstances both inside and outside of Rwanda.
The country’s human rights record has been repeatedly questioned and Kigali has also been accused of launching a proxy war in the Democratic Republic of Congo.
Rwanda has dismissed all these allegations.