Brian Stelter sits down with Andrea Stanley, features editor at Cosmopolitan Magazine, to discuss her latest story: "Is It Possible to Stop a Mass Shooting Before It Happens?" In her piece, Stanley follows "K," a top-secret investigator who has been infiltrating online hate groups to monitor the behavior of men who display signs of violence. During her reporting process, "It was not lost on me that I was going to report on a woman who is tracking some of the worst men in our country," she said. Stanley talks more about her reporting process, Cosmopolitan's coverage of these violent men, and how "the internet has become one of the most dangerous places."

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