On Aug. 20, Alexey Navalny, Russia’s most influential opposition leader, was unconscious after his plane made an emergency landing in the Siberian city of Omsk during a flight to Moscow.

Navalny’s press secretary, Kira Yarmysh, who accompanied him on the trip, said on Twitter that Navalny had consumed a cup of tea in an airport cafe before departure from the city of Tomsk. “That was all he had all day,” she said.

Anonymous TASS Quote Blames Navalny’s Illness on … Navalny

But on the plane, Navalny immediately started feeling sick and asked her to keep talking with him so he could concentrate on her voice. He then walked to the plane’s restroom and a few minutes later started calling for help before passing out, Yarmysh said.

Anonymous TASS Quote Blames Navalny’s Illness on … Navalny

A by a Russian Instagram user , who said he was on the same flight, shows first a photograph of Navalny siting in a cafe and drinking from a paper cup, followed with a footage of the plane’s interior with emergency responders walking in the aisle. A man could be heard screaming for help.

Anonymous TASS Quote Blames Navalny’s Illness on … Navalny

Another video on Telegram channel Mash, popular in Russia, showed an unconscious Navalny being loaded into an ambulance on the tarmac.

Yarmysh tweeted that she suspected poisoning, an explanation that rang true for many in Russia who have seen previous enemies of the Kremlin and President Vladimir Putin targeted with poisons (more below).

Navalny, leader of the Anti-Corruption Foundation, is the highest-profile opposition activist in Russia. Two years ago, his organization accused Prime Minister Dimitry Medvedev of amassing a personal fortune through network of charity funds that collected bribes.

Navalny was admitted to the local Omsk hospital, and doctors said he was in a coma and on ventilation in the intensive care unit. The preliminary diagnosis was “acute toxic poisoning” with an unidentified psychedelic chemical agent, TASS .

But TASS also an anonymous law enforcement source who speculated that Navalny himself was at fault.

“It is not unlikely that he drank or consumed something yesterday himself,” the source said.

The statement was misleading, and there was more to come.

Multiple Telegram channels simultaneously suggestions that Navalny was on an “alcohol drinking rampage” the previous night and his illness was an overdose of a hangover drug.

Yarmysh categorically denied the allegations. “I see that the Kremlin’s Telegram channels are working a new fake, that Navalny allegedly drunk a lot the night before and that today he took a hangover pill, causing the poisoning. That is not true. He did not drink yesterday, and he did not take any pills today,” she .

In a group photo inside the bus that drove Navalny from the cafe to the plane, he appears sharp and smiling with no visible signs of sickness or a “hangover.”

The Kremlin’s press secretary, Dmitry Peskov, journalists that the “best doctors in Omsk” are taking care of Navalny and that he will be treated “just like any other citizen.” Asked whether Putin was briefed, Peskov said, “There was no need for a special briefing” but that president received a regular media monitoring report.

Peskov said that should Navalny’s representatives request his transportation to a foreign hospital, permission will be “immediately granted.”

Navalny’s primary physician, Anastasy Vasilyeva, responded to Peskov on Twitter, saying “[W]e have requested medical documentation to transfer Navalny to a leading Toxicology center in Europe, but the hospital denied providing any data to his wife or me.”

Local news media in Omsk, citing the hospital administration, there were no plans to transport Navalny to Moscow.

According to the Telegram channel , Navalny was in coma with brain swelling. Tests showed the presence of a neurotoxin the lab was unable to identify, the channel reported.

The Omsk hospital’s deputy chief reporters that “the doctors are fighting for Navalny’s life.” His wife, who flew in from Moscow, was to see him after initially being refused because her husband hadn’t signed a consent form for visitations.

Navalny has been before with zelyonka, a type of antiseptic that leaves a lasting green stain on the skin and which is often used against Russian opposition figures. While the intent of such attacks is humiliation more than injury, Navalny he lost 80 percent of his vision in his right eye after one zelyonka attack in 2017.

If Navalny was poisoned, the latest incident would fit a deadly pattern tied to Russian operatives.