Putin merely banished him to hard labor in an arctic gulag. Temps were said to not be colder than -32C. His death is an unfortunate coincidence and had nothing to do with the conditions Putin forced on him, comrade.
Considering Navalny was to be exchanged for a russian spy, I don't believe that his death was intended. His location propably was chosen because it would isolate him and prevent any contact with his handlers.
Embezzlement, fraud, violating probation, contempt of court, inciting and financing extremism, creating an illegal NGO, rehabilitation of Nazism, the list goes on. He broke the law repeatedly and brazenly, and he thought he could do so with impunity because he was the darling of the West and he thought they would protect him. All i can say is, the little fascist Guaido wannabe fucked around and found out.
Find me any place in Russia that doesn't go below -32C in the winter. Or are you saying Russia is right to have annexed Crimea, so they can have access to warmer climates and build prisons there?