MOSCOW — To the German chancellor, Angela Merkel, what befell the Russian opposition leader, Aleksei A. Navalny, was alarmingly simple: He was poisoned with a weapons-grade nerve agent in an attempted murder.
To Russian officials and commentators on state news media, anxious to deny any Kremlin role and offer a wide range of alternative theories, it was not nearly so straightforward — the Germans had poisoned Mr. Navalny, or he had poisoned himself, or he was not poisoned at all.
Though dismissed by critics of the Russian government as dust thrown up to cover the truth, such flurries of evidence-free theories have become a standard response to accusations of Moscow’s malfeasance, whether it is election meddling, military interventions, assassinations or the repression of the domestic opposition.
Mr. Navalny “and his supporters are putting on a big theater play,” a Russian scientist, Leonid Rink, said in an interview on Russian state television.
Mr. Rink, identified as one of the developers of the Novichok group of nerve agents, ventured that Mr. Navalny had poisoned himself — though the poison is believed to be closely held by the Russian security services and almost impossible for a civilian to obtain.
In other explanations offered on state media, an enemy of Russia could have poisoned Mr. Navalny, or fabricated a poisoning that never occurred, with the nefarious goal of embarrassing the Kremlin and harming relations with Germany.
And so it went on Thursday, a day after German officials announced that after thorough analysis, their military’s chemical weapons specialists had reached the unequivocal conclusion that Mr. Navalny had been poisoned with Novichok. That finding laid responsibility squarely at the Kremlin’s doorstep.
The by-now-familiar Russian tactic is to fill the media with so many possibilities that people do not know what to believe. A range of theoretically possible but improbable alternative explanations turns up on prime-time Russian television, churning out a thick fog of uncertainty.
It was possible, Mr. Rink said, given the expertise of German chemists, that they copied the Russian nerve agent and poisoned Mr. Navalny after he had arrived in Germany. In that scenario, Mr. Navalny was either poisoned first with another substance in Russia or, again, poisoned himself as part of the ruse, Mr. Rink said.
“Somebody is sitting at a table now celebrating a successful operation,” he concluded.
Another familiar participant in the media circus, Margarita Simonyan, the editor in chief of Russia Today, expressed a wide-eyed uncertainty about the case, suggesting that there was no way to form an impartial view.
“I don’t know who poisoned Navalny and if he was poisoned at all,” she wrote in a Twitter post on Thursday. “In the absence of hard facts, a person always chooses who to believe, based exclusively on personal sympathy and preference.”
In 2014, President Vladimir V. Putin denied that men in unmarked uniforms turning up on the Ukrainian peninsula of Crimea were Russian soldiers, saying they were local militia or members of a motorcycle gang. Some time later, he coyly conceded that they were Russian soldiers, the vanguard of Russia’s military seizure of the territory.
That same year, Russia denied backing a separatist insurgency in an area of eastern Ukraine called Donbass, and denied supplying the rebels with the anti-aircraft missile system that shot down a Malaysia Airlines plane, killing 298 people — despite ample evidence to the contrary and the conclusions of Western governments.
The Kremlin and state media floated an array of alternative explanations and conspiracy theories about the flight — for example, that the Ukrainian military had shot it down. Russian state television broadcast a theory that the Central Intelligence Agency had downed a plane filled with corpses to justify the imposition of economic sanctions.
After the former double agent Sergei V. Skripal was poisoned with Novichok in Britain in 2018, the British government identified two Russian military intelligence officers as the attackers. The pair went on Russia Today to deny being spies and say they had visited the English city where Mr. Skripal lived just to see the spire of Salisbury Cathedral.
Ms. Simonyan, who conducted the interview, did not mention glaring weaknesses in their story and suggested Western governments might be homophobic for raising suspicions about young men traveling together. Other Russian media reports suggested that the British had poisoned Mr. Skripal.
In the case of Mr. Navalny’s illness, the formal Russian government response has been to ask Germany for additional evidence.
“We are hoping it’s possible to establish the cause of what happened,” Dmitri S. Peskov, the Kremlin spokesman, told journalists on Thursday. “We are interested in this, we want this, and for this we need information from Germany.”
The Russian Foreign Ministry issued a statement essentially accusing Germany of making reckless claims.
“Yet again, we become witnesses of a situation where in place of careful work, based on facts and evidence and cooperation between law enforcement organs and medical institutions, our partners prefer loud, public announcements,” the statement said. The Germans had not produced “any facts at all,” the statement said.
Within a few hours of the German revelation, more elaborate responses came from commentators on Russian media.
Mr. Rink said the German statement was untrue because Mr. Navalny could not have survived a Novichok poisoning, despite documented cases of such survival. “The comrade would be resting in a different place now,” he said.
Olga Skabeeva, a state television talk show host, noting that Mr. Navalny first took ill on an airline flight, questioned in a post on social media why, if such a dangerous poison were used, no other passengers and none of the doctors who treated him were sickened. “Novichok, they told us after Salisbury, is very dangerous.”
Mr. Navalny’s family and supporters have surmised that the poison was dropped into some tea he bought in the airport in Novosibirsk, in Siberia — the only thing he consumed that morning. He was flown to Germany for treatment two days later.
On Thursday, the president of Belarus, Aleksandr G. Lukashenko, who has been currying favor with the Russian government to win support against street protesters, contributed his own theory.
He told the visiting Russian prime minister that his security service had intercepted a telephone call of Ms. Merkel admitting the poisoning was falsified.
“We caught an interesting conversation,” he said in comments carried by the Tass news agency. “It speaks about this falsification. There was no poisoning of Navalny.”
Russian doctors have suggested that Mr. Navalny lapsed into a coma because of low blood sugar.
“If the Kremlin wants its denials to be taken seriously, it ought not to have lied about Crimea, about Donbass,” the Malaysian airliner and previous poisonings, Sam Greene, the director of the Russia Institute at King’s College London, wrote on Twitter. “Whatever else may be going on in the world, Moscow’s credibility problem is of its own making.”