Russians have always had a penchant for rumor and conspiracies, underpinned by the presumption that official news is deeply doctored by the Kremlin. So it is not surprising that within hours of the first reports of a plane crashing with somebody as notorious as Yevgeny Prigozhin listed as a passenger, speculation spread like a Siberian wildfire. Perhaps he was not on the plane and had staged his death to disappear. Or maybe President Vladimir Putin now had Mr. Prigozhin in a secret dungeon. Or the Ukrainians on whom he unleashed his mercenaries blew the plane up.

Nothing seemed impossible with Mr. Prigozhin, a racketeer-turned-caterer-turned-warlord-and-Putin crony who sent his mercenary Wagner Group on an audacious march on Moscow in June to settle scores with Russia’s military leaders. There was no shortage of people who probably wished him dead, including those same Russian military leaders, or the Ukrainians, or the African and Syrian rebels savaged by his mercenaries.

But as is so often the case with atrocities in Mr. Putin’s Russia, the plane crash was probably exactly what it appeared to be: the assassination of a nettlesome rival by the ruthless ruler. That may never be proved; Mr. Putin may choose to posthumously honor Mr. Prigozhin as a patriot, or at least to blame his death on his pet villains, Ukrainian “fascists” and a deceitful and degenerate West. But for now, most observers believe the evidence, motive and means point to Mr. Putin.

In the brutal logic of dictatorial rule, Mr. Putin would have had no choice. Though Mr. Prigozhin was careful to display total fealty to the president even when he ordered his forces on a “march for justice” in June, it was an open rebellion against Mr. Putin’s rule, and the president’s first public reaction was to warn — without naming Mr. Prigozhin — that those who prepared the mutiny “have betrayed Russia.” In Mr. Putin’s lexicon, that’s a death sentence. He is Russia.

Mr. Putin played the aftermath with the same cunning that has kept him in power for more than 20 years, allowing the warlord to leave for Belarus after the mutiny, dropping formal charges against him, inviting him to a three-hour chat at the Kremlin, then leaving him free to move about Russia.

Mr. Prigozhin seemed to conclude that he had been forgiven. He claimed to have made an appearance at a Russia-Africa summit in St. Petersburg, though there is no firm evidence he was there. Then, two days before the plane crash, he released a new recruitment video for the Wagner Group, purportedly filmed in Africa. Against the backdrop of a bare field, Mr. Prigozhin appeared decked out in the full commando kit he favored for such videos before the mutiny.

“We’re working,” he intoned in his tough-guy growl. “Temperature 50 plus, as we like it. Wagner is carrying out RSO (reconnaissance and search operations). Making Russia even greater on all continents, and Africa even freer.”

After that display of bravado, Mr. Putin apparently made his first move on Wednesday — two months to the day since the mutiny — when Gen. Sergei Surovikin, a former commander of the Ukraine operation, was reportedly demoted. He had dropped from public view right after the mutiny. And after 6 p.m. that evening, Mr. Prigozhin’s plane — an executive jet he frequently used, and said to be the same one on which he flew to Belarus after the aborted mutiny — dropped out of the sky.

An unconfirmed video of the incident posted online showed the plane crashing to earth, evidently with only one wing. And witnesses reported hearing two explosions, raising the possibility that the jet had been shot down by an antiaircraft battery. Soon after, official media reported that Mr. Prigozhin was on the list of seven passengers and three crewmen aboard. There were reports that the military commander of the Wagner Group, Dmitri Utkin, said to be an open admirer of Nazi Germany, was also on board.

The seemingly unavoidable conclusion is that Mr. Prigozhin’s fate was sealed two months ago. Whatever the cause of this crash, Mr. Putin’s army of sycophants and cronies are certain to understand the message: No amount of bootlicking, at which Mr. Prigozhin had been a master, and no long history of loyal service, whether providing food for the Kremlin or running a private army, would be enough to protect anyone who turned on the don.

It has long been clear that, in Putin’s Russia, betrayal is unforgivable. The radioactive polonium used to kill one K.G.B. defector, Alexander Litvinenko, and the Novichok nerve agent used in an attempt on another, Sergei Skripal, were meant to leave no doubt about who did it or why. And efforts to silence his most tenacious opponent, Alexei Navalny, by an attempted poisoning, and a draconian prison sentence, are clear signs of near total intolerance for any dissent.

The need to enforce personal loyalty has become even more critical with the invasion of Ukraine, an operation linked directly to Mr. Putin that is amassing a terrible cost in lives, treasure and international standing.

Given Mr. Prigozhin’s sordid history, it remains possible that new and perhaps surprising revelations about this crash still lie ahead. But if it turns out that this was not Mr. Putin’s doing, it may only be because someone beat him to it.