Russian soldiers fighting in Ukraine have been supported on the battlefield by tens of thousands of mercenaries from a group of contractors led by a businessman and longtime affiliate of President Vladimir Putin. The Wagner Group is a private military company under the control of Yevgeny Prigozhin that cut its teeth in deployments to Crimea and eastern Ukraine's Donbas region in 2014. Charlie D'Agata speaks to London School of Economics Russian expert Jeff Hawn about the onetime allies who are now bitter enemies.
