When Ukrainian president Volodymyr Zelensky toured Bucha and Irpin last Monday, at his side was his aide Serhiy Leshchenko. I first met Serhiy in 2014, through Mustafa Nayyem, when the two of them successfully ran for the Ukrainian parliament, the Rada, on the heels of the Maidan revolution. Like Mustafa, Serhiy had also been a star investigative journalist, exposing corruption at the highest levels of the Ukrainian government. Even while he served in government, however, Serhiy’s investigative instincts never left him. In August 2016, he revealed the secret ledgers showing illicit cash payments to Paul Manafort, which ended Manafort’s run as Donald Trump’s campaign manager and began his downfall.