President Vladimir Putin said on Thursday that explosive traces were discovered in the remains of Wagner mercenary chief Yevgeny Prigozhin and his crew after their plane crashed over Russia in August.
Prigozhin’s plane crashed in August between Moscow and Saint Petersburg, two months after he staged a brief rebellion against Russia’s top military hierarchy.
Critics of the Kremlin and Western countries have suspected collusion.
Putin’s remarks were the first important update on Russia’s crash inquiry.
“The head of the Investigative Committee reported to me a few days ago,” Putin said at a meeting of the Valdai Discussion Club.
“Fragments of hand grenades were found in the bodies of the victims of the air disaster. There was no external impact on the plane.”
Russian investigators have said they are probing all possible scenarios surrounding the crash, including premeditated murder.
Putin on Thursday criticised investigators for not conducting alcohol and drug tests on Prigozhin and the nine other victims of the crash.
He also alleged that five kilogrammes of cocaine were found at the Wagner offices after the mercenary group’s short-lived rebellion.
“A blood test for alcohol was not done,” Putin said.
“Even though we know that after the famous events in the (Wagner) company in Saint Petersburg, the FSB (security service) found not only 10 billion in cash, but also five kilogrammes of cocaine,” Putin said.
Prigozhin led an armed rebellion against Moscow’s military leadership in June, the biggest threat to Putin’s two-decade rule.
After the crash, Putin described him as a man who had made “serious mistakes in his life but he achieved the right results.”
The Kremlin has dismissed suggestions that it orchestrated the crash in revenge for Wagner’s march on Moscow.
Russia has a history of mysterious deaths of Kremlin opponents under Putin.