Watch CNN's harrowing report uncovering evidence of human rights atrocities

CNN has uncovered disturbing evidence of human rights atrocities by Russian mercenaries in the Central African Republic. CNN's Clarissa Ward and her team were denied entry to the country because of CNN's previous reporting on the activities of the mercenaries. But working with local journalists and an independent investigative group The Sentry, CNN has assembled evidence of a pattern of abuses, which one UN expert says may amount to war crimes.