Legendary war correspondent Orkhan Dzhemal, 51, award-winning filmmaker Alexander Rastorguyev, 47, and cameraman Kirill Radchenko, 33, were killed on Monday night when their vehicle was ambushed in the war-torn country.
Government authorities suspect members of Seleka, a loose group of mostly Muslim rebels that controls more than half of CAR, according to Russian and CAR state media.
Citing the driver, who survived, local officials claimed the journalists were killed by Arabic-speaking “turbaned gunmen” after resisting the the theft of their vehicle.
They had ventured past a government checkpoint into rebel-controlled territory despite warnings from soldiers, according to the Russian foreign ministry.
A local website published a photograph showing the bloodied corpses of two of the men in the back of a truck.
One of the men’s editors said he had been suspicious of their driver after they were shaken down for a bribe by police. Besides film equipment, the group was carrying $8,500 in cash.
But some in Russia have raised concerns that their killing could be connected to the sensitive topic of their report.
In April, another journalist who had reported on the same mercenaries died in a fall from his balcony in Yekaterinburg a day after he said he saw armed men in his stairwell.
The trio was making a film for TsUR, an investigative media centre funded by Mikhail Khodorkovsky, a former oligarch who was imprisoned for a decade after publicly disagreeing with Russian leader Vladimir Putin.
“I will make efforts to identify those responsible,” Mr Khodorkovsky, who now lives outside Russia, wrote on social media, giving no further details on what he intended to do.
Their topic was the Wagner mercenary group that was hit with US airstrikes earlier this year while attacking an oilfield in Syria, where it served as “shock troops” for Mr Putin’s ally Bashar Assad.
Dmitry Utkin, who was sanctioned by the United States as Wagner’s leader, has been photographed with Mr Putin and was employed by Yevgeny Prigozhin, a catering magnate known as “Putin’s chef” for serving the president during state dinners.
A US grand jury indicted Mr Prigozhin in February for running a Russian Internet troll factory that tried to turn voters against Hillary Clinton.
A foreign ministry spokeswoman denied that the journalists’ death was connected to their investigation of Wagner. Russian state media have avoided mentioning the group in reporting the incident.
Russia has taken on an official role in CAR since December last year, when it was authorised by the UN to provide government forces with weapons and training. It said it has deployed “five military and 170 civilian instructors to train CAR soldiers”.
But researchers from the Moscow-based Conflict Intelligence Team and Transparency International have raised suspicions that Wagner was guarding diamond mines in rebel territory.
In April, locals blocked a Russian-registered Cessna airplane the government said was carrying Russian military advisers from taking off in rebel-held Kaga Bandoro, which is near diamond deposits. A CAR official said Russian advisers had been there for peace negotiations with rebels.
Some reports held that the three journalists had also travelled to Kaga Bandoro.
TsUR said they had been trying to set up filming at the Ndassima gold fields, which Russia is reportedly involved in securing.
The foreign ministry said Russia and the CAR began joint “exploratory mining concessions” this year, but did not specify where.
Two Russia-linked mining companies were registered following the agreement to develop CAR’s natural resources with Russia, according to Transparency International.
The NGO’s deputy director Ilya Shumanov said one of the companies was owned by a security firm, which he called “further evidence that the deployment of private military companies and Russians’ entry into the the CAR mining sector are of a piece”.
In Syria, a company linked to the Wagner group had a deal with the government to receive 25 per cent of the profits from oil and gas fields its contractors could capture, according to a contract seen by AP and Russian media.
The three Russian correspondents had previously been turned away from Wagner troops’ reported headquarters in Jean-Bedel Bokassa’s palace in Berengo, where the late dictator was accused of feeding enemies to lions and crocodiles or eating their flesh himself.
Russia has been trying to return some of its Soviet-era influence in Africa, including through arms deals like the $1bn sale of Su-24 fighter jets to Sudan.
CAR president Faustin-Archange Touadéra met Mr Putin at an economic gathering in St Petersburg in May.
Friends and well-wishers have been laying flowers in memory of the slain journalists at a monument to frontline reporters in downtown Moscow. Their bodies will be brought back to Russia on Friday.
Mr Rastorguyev had made films about life in the Russian provinces as well as Moscow’s wars in Ukraine and Chechnya.
Mr Radchenko had covered the Ukrainian conflict and also Russia’s military intervention in Syria.
Mr Dzhemal, the son of a well-known Muslim activist, had reported from these conflicts as well as those in Georgia, Somalia, Libya, Afghanistan and Iraq.
In an obituary, author Mikhail Zygar, a former colleague at Russian Newsweek and TV Rain, wrote that “only the heroes of children’s books are as honest and foolhardy” as the late war correspondent was.