Russian investigators have yet to determine the official cause of opposition leader Alexei Navalny's death, his spokeswoman said on Monday, after prison authorities said he suddenly dropped dead following a walk in the «Polar Wolf» penal colony.
Navalny's death robs Russia's disparate opposition of its most charismatic and courageous leader as President Vladimir Putin prepares for an election that will keep him in power until at least 2030.
The West and Navalny's supporters have dismissed the Russian prison service's statement on Friday that the 47-year-old had lost consciousness and died. Western leaders have said Putin is responsible for Navalny's death, a stance the Kremlin condemned on Monday as «obnoxious».
Putin has made no public comment on Navalny's death but it has further deepened a gaping schism in relations between Moscow and the West caused by the nearly two-year Ukraine war.
Navalny's mother, Lyudmila, was told on Saturday at the prison colony that he had perished from «sudden death syndrome», a vague term for different heart conditions that end in death, according to Navalny's team.
Navalny's spokeswoman, Kira Yarmysh, said his 69-year-old mother and lawyers were informed that the official verification of the cause of death had been extended and that it was unclear how long it would take.
«The cause of death is 'undetermined',» said Yarmysh, who accused the Russian authorities of lying and stalling.
His mother and lawyers were not