How serious is the U.S. about investigating Russian war crimes in Ukraine? They put Eli Rosenbaum on the case. He's best known for directing the Department of Justice special investigations unit which tracked down Nazis who had gone into hiding after World War II.He lays out the challenges of conducting an investigation in the midst of an ongoing war.This episode also features reporting from NPR's Jason Beaubien and Brian Mann on Russian airstrikes that killed Ukrainian civilians.In participating regions, you'll also hear a local news segment to help you make sense of what's going on in your community.Email us at considerthis@npr.org.