Gambaryan and his colleague Nadeem Anjarwalla, Binance’s regional manager for Africa and a Kenyan-British citizen, were initially placed under house arrest. But when Anjarwalla escaped under mysterious circumstances in March, Gambaryan was transferred to the notoriously dangerous Kuje prison and charged with tax evasion and money laundering — apparently as a scapegoat for his employer, whom Nigerian authorities have accused, without evidence, of sinking the value of the national currency, the naira.