An Alabama man who coerced girls to expose themselves over the Internet, including a 13-year-old Sudbury girl, will spend time behind bars. Christopher Gunn was found guilty of 14 counts of interstate extortion, seven counts of stalking and two counts of child porn possession. The 32-year-old repeatedly used Internet chat rooms and social media to threaten hundreds of girls aged nine to 16. In the Sudbury case Gunn claimed to be Justin Beiber and promised the teenager backstage concert passes if she exposed herself to him on a webcam. Gunn will be sentenced November 20th in Alabama.