Vladimir Kara-Murza, an opposition activist in Russia, suddenly fell ill and collapsed at his Moscow office on Tuesday, May 26. After being rushed to the hospital, Kara-Murza's condition became critical. On May 28, his father told  RFE/RL, “His kidneys stopped working in the evening. [He] is alive now thanks to an artificial kidney, thanks to hemodialysis… His lungs are being artificially ventilated. He is connected to 10 devices.”
By the end of the following weekend, Kara-Murza's father said his son's condition appears to have stabilized , but he remains in a coma and on life support. Kara-Murza's doctors have determined that transporting him abroad for treatment, as his wife has requested, is not possible in his current condition.
The day before Kara-Murza's hospitalization, the organization Open Russia , where he works as a coordinator, released a hard-hitting exposé about Ramzan Kadyrov's rule in Chechnya. Open Russia, created in September 2014 by former political prisoner and oil oligarch Mikhail Khodorkovsky , defines its mission as the promotion of European political values in Russia. Its new documentary, “The Family,” blasts Kadyrov for presiding over a violent reign of lawlessness.
This sequence of events—the airing of the exposé followed by a sudden decline in health of an Open Russia coordinator—has sparked widespread speculation that Kara-Murza's illness may not be due to natural causes.
A bizarre movie trailer  posted to Instagram by Kadyrov on May 25, just hours after the Open Russia documentary premiered, has further fueled such suspicions. The trailer, for an apparently fake movie called “He Who Doesn’t Understand Will Understand Soon,” mostly features Kadyrov firing an automatic weapon into the air. The trailer was interpreted by political analyst Stanislav Belkovsky as an “indirect threat” against those behind Open Russia‘s film.
Following the brazen assassination of leading Russian opposition figure Boris Nemtsov this February in Moscow, many prominent online voices reflected fears that Vladimir Kara-Murza had been poisoned, in another political killing. Former Moscow correspondent Julia Ioffe tweeted that Russian oppositionists are being hunted down:
Opposition activist and Khodorkovsky's right hand man Vladimir Kara-Murza is in critical condition. Poisoning. It's open season in Russia.
— Julia Ioffe (@juliaioffe) May 27, 2015 
Others immediately mocked such speculations, sometimes using the sarcastic “Coincidence—I think not!” meme borne from a famous line by television journalist Dmitri Kiselyov:
Публицист Владимир Кара-Мурза госпитализирован в критическом состоянии Совпадение? Не думаю! pic.twitter.com/Z4v6s78pvR 
— Николай Зубов (@zubovnik) May 27, 2015 
Publicist Vladimir Kara-Murza hospitalized in critical condition. Coincidence? I think not!
On Friday, FT  reported that Kara-Murza's “friends said they were increasingly convinced he had been poisoned.” In The New Yorker , journalist Masha Gessen tied Kara-Murza's sudden illness to modern Russia's history of alleged assassinations by poison. “Indeed, the larger message of the Nemtsov assassination and the apparent attempted assassination of Kara-Murza,” Gessen wrote, “is that no one is safe.”
On Thursday, former US Ambassador to Russia Michael McFaul appeared on MSNBC's The Rachael Maddow Show. After running through a list of Russian activists, whistle-blowers, and journalists who have died under mysterious circumstances during Putin's rule, Maddow asked for McFaul's perspective on Kara-Murza's sudden illness. “In the spirit of not knowing all the facts, we don't know what happened to Vladimir… but when you add it up and you connect the dots like you just did, it does feel like it is a pattern,” answered McFaul. “For the opposition, it has the obvious chilling effect. People in Russia are scared, and many of them have left the country.”
— Michael McFaul (@McFaul) May 31, 2015 
With the cause of Kara-Murza's affliction still unconfirmed medically, various other rumors have also made rounds on the Russian Internet, often following announcements from Kara-Murza's father.
On May 27, Kara-Murza's father said  he had learned his son's illness “all had to do with his kidneys,” and “it could have been spoiled yogurt or something else.” He added , “I asked the doctors if this could have been a crime. They said that it could have been anything: yesterday's chiburekki, a banana, an apple… I think there was no crime. If there was, we would not be here today talking to you.” However, Kara-Murza's colleague Mikhail Kasyanov, co-chair of opposition party RPR-Parnas, seems unconvinced by this explanation:
Володя Кара-Мурза в тяжелом состоянии в больнице http://t.co/uRQEIGvdFl Глубокая интоксикация от просроченного кефира не бывает.Володя борись
— Михаил Касьянов (@MKasyanov) May 27, 2015 
Volodya [nickname for Vladimir] Kara-Murza is in critical condition in the hospital. Spoiled kefir doesn't cause deep intoxication. Volodya, keep fighting!
On May 28, Kara-Murza's father then stated  that his son had begun taking anti-depressants after the murder of his friend Boris Nemtsov, and doctors suspected these might have caused his illness. Medical samples have since been sent  to Europe for further testing, which could help determine if Kara-Murza was poisoned or is suffering from some other ailment.
As rumors, suspicions, and fears swirl online and in Moscow, some analysts are wary of leaping to conclusions. “There is a worrying if perhaps understandable tendency to see murderous plots at every turn when it comes to Russia and those critical of Kadyrov or the Kremlin, but I think it is too soon to be making any such rushes to judgement when it comes to Vladimir Kara-Murza,” NYU professor and Russian security expert Mark Galeotti told RuNet Echo. “Let's wait for proper medical assessments before constructing fantasy scenarios that say more about our own assumptions than anything else,” Galeotti continued. “Kadyrov certainly is all too willing to resort to murder, but his is the way of the gun and the bomb, not the subtleties of poison.”
Nonetheless, Kara-Murza's sudden illness, on the heels of Nemtsov's assassination, is certain to have many of Russia's opposition activists thinking long and hard about what continuing their work in today's political climate could mean for their own safety.