Already notorious as an agent of market mayhem, the crypto industry has now unleashed political havoc, too, upending a critical general election in Montenegro, a troubled Balkan nation struggling to shake off the grip of organized crime and the influence of Russia. Kwon, but later acknowledged he had known him since 2018 and invested money with him on behalf of an investment fund he says he was working for in Singapore — “he cheated us,” Mr. Milan Knezevic, the leader of the pro-Russian bloc that finished second in the election, said he relished his group’s unexpectedly strong result, achieved in part because of the disruption caused by Mr