MIAMI — For the Polk County sheriff’s office, which has been investigating the cyberbullying suicide of a 12-year-old Florida girl, the Facebook comment was impossible to disregard.

In Internet shorthand it began “Yes, ik” — I know — “I bullied Rebecca nd she killed herself.” The writer concluded that she didn’t care, using an obscenity to make the point and a heart as a perverse flourish. Five weeks ago, Rebecca Ann Sedwick, a seventh grader in Lakeland in central Florida, jumped to her death from an abandoned cement factory silo after enduring a year, on and off, of face-to-face and online bullying.Read more…