The Wall Street Journal’s latest documentary “Shadow Men: Inside Russia’s Secret War Company” goes deep inside the lethal global expansion of the Russian private military company Wagner — tracing the group's evolution from a small, guns-for-hire operation into a sprawling network of businesses that has been active on four continents. Through interviews with current and former Wagner fighters, government insiders, victims of attacks and war crimes investigators, the film reveals how the group is hiding the flow of riches and resources through a complex network of front companies that ultimately connect to the Kremlin.