Russia's Investigation Committee has confirmed Yevgeny Prigozhin was among ten people killed in a plane crash near Moscow on Wednesday.
Mr Prigozhin, who in June led an armed mutiny against Russia's military leadership, was leader of the Wagner mercenary group.
The committee said the results of genetic tests had confirmed the identities of the ten people who died in the crash.
"Molecular-genetic examinations have been completed as part of the investigation into the plane crash in the Tver region," said spokeswoman Svetlana Petrenko.
"According to their results, the identities of all ten victims were established, they correspond to the list stated in the flight list," she added.
Among the other nine people listed onboard the Embraer private jet was Dmitry Utkin, who managed Wagner's operations and allegedly served in Russian military intelligence.
Russian officials opened an investigation into air traffic violations after the crash but have otherwise not disclosed details about its possible cause.
Kremlin spokesman Dmitry Peskov described the incident as "tragic" to reporters on Friday, calling rumours of possible foul play an "absolute lie".
Mr Peskov's comments came as the Kremlin appeared to rein in groups like Wagner, with a presidential decree signed Friday stipulating that paramilitary fighters will have to swear an oath to the Russian flag.
In an address on Thursday, Russian President Vladimir Putin said he had known Mr Prigozhin - once a loyal ally - since the early 1990s, describing him as a man who made mistakes but "achieved results".
However, his comments did little to stem mounting questions and anger over the mercenary's chief's death, with makeshift shrines to Mr Prigozhin springing up across Russian cities.
Wagner forces, which Moscow used to carry out some of the Ukraine conflict's bloodiest battles, also maintained a significant military presence in Africa.
Similar memorials were spotted across the country, in cities like Perm and Saint Petersburg - Russia's former imperial capital and Mr Prigozhin's birthplace.
On Friday, investigators announced they had recovered ten bodies, as well as flight recorders from the scene.
Mr Putin broke his silence on the crash in his Thursday address, offering condolences to the families of the ten people onboard and describing the incident as a "tragedy".
He said Mr Prigozhin had made some "serious mistakes in his life" and had had a "complicated fate".
Read more: Prigozhin: Russia's mercenary supremo turned Kremlin enemy
