MOSCOW When Russian opposition politician Alexei Navalny collapsed in an airplane bathroom Thursday, his supporters immediately suspected poisoning. If true, he wouldnt be the first prominent, outspoken Russian to be the target of toxic attack. A British inquiry found that Russian agents had killed Litvinenko, probably with President Vladimir Putin's approval. At the time of Litvinenkos poisoning, he had been investigating the killing of Russian journalist Anna Politkovskaya three weeks earlier. PYOTR VERZILOVVerzilov, a member of Russian protest group Pussy Riot, ended up in an intensive care unit after a suspected poisoning in 2018 and had to be flown to Berlin for treatment.