Wagner warlord Yevgeny Prigozhin, who led a failed uprising against the Kremlin exactly two months ago, was on board a plane that crashed on Wednesday, according to Russian officials -- raising questions as to exactly how the disaster occurred.
The crash took place northwest of Moscow and killed all on board, said Russia's aviation agency, including Prigozhin, chief of the mercenary group that gained prominence for its brutal methods worldwide and its battleground victories in the Ukraine war.
Here's what we know so far.
What happened?
The plane was a private Embraer jet carrying seven passengers and three crew members, according to Russia's emergency services ministry.
It had departed from Moscow and was en route to St. Petersburg when it crashed near the village of Kuzhenkino, in Russia's western Tver region, Russian officials said. Flight data shows the plane reached an altitude of some 28,000 feet before it suddenly stopped transmitting tracking details.
The bodies of eight people have been found at the crash site, according to Russian state media. The official state news agency TASS reported the plane "burned up" on impact. It had been in the air for about half an hour.
Video published by Russian state media outlet RIA Novosti showed a plane plummeting with one wing missing. CNN is unable to confirm the authenticity of the video, but RIA Novosti claimed it was the moment that an Embraer jet fell from the sky over the Tver region.
It's not yet clear what caused the plane to crash. Russian authorities said they are investigating and conducting search operations.
"It's coming down quickly in a spin, and it's trailing a lot of smoke. So, this is an aircraft that was on fire. And it looks like some structural pieces, aerodynamic surfaces, were missing," veteran science and aerospace reporter Miles O'Brien told CNN after reviewing footage of the plane's fall.
"An aircraft like this ... they just don't catastrophically drop out of the sky without something very unusual happening," he added.
It could be caused by an explosion either inside or outside the aircraft, O'Brien added -- like an explosive going off on board, or the aircraft being hit by a missile.
David Soucie, a former safety inspector with the US Federal Aviation Administration, echoed this possibility, saying the plane's fall looked like it had only one wing left.
Was Prigozhin on board?
Prigozhin and several top Wagner lieutenants were named on a list of passengers shared by Russia's aviation agency.
A Telegram channel linked to Wagner, which had previously carried the group's propaganda videos, also issued a statement saying Prigozhin had been killed. CNN is unable to confirm the claim.
Other channels associated with Prigozhin and Wagner, including his official Telegram channel, have remained silent.
But there are other clues linking the warlord and the crash.
Another video released by RIA Novosti purports to show the crash site, where the last four digits of a registration number are visible on the plane engine debris: 2795. Prigozhin's own plane, linked to his companies and the Wagner group, is registered as RA-02795.
Was this payback?
The crash comes exactly two months to the day after Prigozhin's attempted mutiny against Russia's military leadership.
Prigozhin and his Wagner troops had 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.
It marked the biggest challenge to Russian President Vladimir Putin's rule in 23 years. But it also painted a target on Prigozhin's back, with some experts speculating the warlord was a dead man walking.
Even US President Joe Biden suggested on Wednesday that Putin may have been involved in the crash. "I don't know for a fact what happened, but I'm not surprised," he said.
CIA Director Bill Burns and Secretary of State Antony Blinken have made similar comments, pointing out Putin's long history of payback and the frequency with which Russian critics or dissidents die in mysterious circumstances.
Bill Browder, a Putin critic and formerly the largest foreign investor in Russia before he was expelled from the country, said he was surprised Prigozhin survived for as long as he did after the rebellion. Other Wagner leaders and Prigozhin allies may now be either on the run or in hiding, he said.
What's the public reaction so far?
Prigozhin and Wagner have their share of supporters among the Russian public -- which was evident during the failed insurrection. In cities briefly occupied by Wagner, videos showed residents cheering them on, taking pictures with fighters, and flagging down Prigozhin's car just to shake his hand.
On Wednesday night, people gathered in St. Petersburg to leave tributes for Prigozhin such as flowers, candles and Wagner chevron patches. Video showemd members of the public unfurling a large banner outside Wagner's headquarters that read, "Wagner PMC. We are together."
Photos show a range of people mourning at the site, including young men, couples and teenagers; some are clearly distressed, embracing each other.
The news is likely to meet a far different reaction in Ukraine. Wagner forces were heavily involved in taking several Ukrainian towns early this year, delivering tangible progress for the Russian side -- but often at the expense of sending waves of mercenaries into what Prigozhin called "the meat grinder".
"There will be no tears shed here at all, if indeed he has died," said CNN's Chief International Security Correspondent Nick Paton Walsh, currently based in Ukraine. He added that one Ukrainian soldier on the front lines had already texted him Wednesday to celebrate the news.