Just over halfway through this year, Baltimore has crossed a frightening threshold: more than 200 city residents have been murdered. What can be done to stop the violence? Daniel Webster , director of the Johns Hopkins Center for Gun Policy and Research , discusses the obstacles posed by stolen guns and repeat offenders. And Erickka Bridgeford , one of the organizers of a 72-hour ceasefire this coming weekend, explains how she is making a pitch for peace.