Russian President Vladimir Putin suggested Thursday that it was not an “external” attack that crashed the plane carrying Wagner warlord Yevgeny Prigozhin in August, but hand grenades within the aircraft.

Speaking at the Valdai Forum in Sochi, Putin said the “chairman of the investigative committee just reported a few days ago that the fragments of hand grenades were found in the bodies of the victims. There was no external influence on the plane, it is an established fact.”

Prigozhin, who led a failed uprising against the Kremlin, was among the 10 people on board the private plane which crashed in a field northwest of Moscow in August while en route to St. Petersburg. All on board, including Prigozhin and his top aides, were killed.

The Russian leader, whose government has denied involvement in the crash, did not detail how grenades might have exploded on the plane, but said that he thought investigators should have performed drug or alcohol tests on the bodies of the victims.

“I repeat, in my opinion such an examination should have been carried out but it wasn’t,” he said, also saying that “10 billion in cash and 5 kilos of cocaine” had previously been found by Russian security forces in Wagner’s office in St Petersburg.

Putin said the chairman of the investigation committee said it was ok to “share this information publicly” as it was “an established fact.”

The crash came two months to the day after Prigozhin’s attempted mutiny against Russia’s military leadership, which posed the biggest challenge to Putin’s rule in decades.

In June, Prigozhin and his Wagner troops seized key military sites and marched toward Moscow, where the Kremlin had deployed heavily armed troops to the streets. But before they could face off, a deal was struck that ended the rebellion and sent Prigozhin and his fighters to neighboring Belarus.

Following the deadly crash, Russian officials said they were considering various scenarios surrounding the incident, including the possibility of a “deliberate atrocity,” Kremlin spokesman Dmitry Peskov told reporters in late August.

Peskov has denied claims that the Kremlin might have been involved in the plane’s demise, calling such speculation an “absolute lie.”