Blood and Honor by Michael Newton
This third book in The Bureau series spans the era of "public enemies" and the global rush toward World War II. Declan O'Hara is transferred to Chicago, working under Melvin Purvis in pursuit of John Dillinger and associated bandits. Aloysius Gantt remains at FBI headquarters but ranges far afield to capture Machine Gun Kelly and the Barker-Karpis Gang.
Edgar Hoover faces opposition in Congress and must prove his prowess as a G-man while expanding domestic surveillance on orders fro President FDR. Ike Sawyer remains with the Federal Bureau of Narcotics and plays a role in prosecuting Lepke Buchalter. Greg Jordan and his brothers face peril as prosecution of "Murder Incorporated" threatens the Syndicate's moves in Cuba and Nevada.
In the USSR, Leonid Babin continues his rise through secret police ranks, navigating the pitfalls of show trials, the Spanish Civil War, and Russia's expansion before Hitler betrays Stalin with "Operation Barbarossa." The FBI's Special Intelligence Service prepares to fight fascism in Latin America, with O'Hara assigned to foreign duty.