A private jet crashed over Russia on Wednesday, killing all 10 people on board, emergency officials said. Mercenary chief Yevgeny Prigozhin was on the passenger list, but it wasn’t immediately clear if he was on board.

Unconfirmed media reports said the jet belonged to Prigozhin, founder of the Wagner private military company.

Russia’s state news agency Tass cited emergency officials as saying that the plane carried three pilots and seven passengers. It was not clear if Prigozhin was among those on board, though Russia’s civilian aviation regulator, Rosaviatsia, said he was on the passenger list.

The plane was en route from Moscow to St. Petersburg and went down in the Tver region, more than 100 kilometers (60 miles) north of the capital. Authorities are investigating.

Prigozhin, 62, spearheaded a mutiny against Russia’s top army brass on June 23-24 which President Vladimir Putin said could have tipped Russia into civil war.

The mutiny was ended by negotiations and an apparent Kremlin deal which saw Prigozhin agree to relocate to neighbouring Belarus. But he had appeared to move freely inside Russia after the deal nonetheless.

Prigozhin, who had sought to topple Defence Minister Sergei Shoigu and Valery Gerasimov, chief of the general staff, on Monday posted a video address which he suggested was shot in Africa.

SOURCE: AP, REUTERS AND AGENCIES