Editor’s Note: An earlier version of this story incorrectly stated that Andriy Portnov is wanted in Ukraine for embezzlement. He was wanted on suspicion of embezzlement, but the case against him was closed in 2016. According to UNIAN and other news agencies, a criminal case on suspected treason was opened in March 2018 by the Crimean prosecutor’s office in exile and was being pursued by the Security Service of Ukraine, known as the SBU.

Home to Chechen emigres and Russian contract killers, the Austrian capital of Vienna has lately welcomed a new breed: self-proclaimed Ukrainian political dissidents.