An anonymous reader writes "Facebook has added sleuthing to its array of data-mining capabilities, scanning your posts and chats for criminal activity. If the social-networking giant detects suspicious behavior, it flags the content and determines if further steps, such as informing the police, are required. Reuters provides an example of how the software was used in March: 'A man in his early 30s was chatting about sex with a 13-year-old South Florida girl and planned to meet her after middle-school classes the next day. Facebook's extensive but little-discussed technology for scanning postings and chats for criminal activity automatically flagged the conversation for employees, who read it and quickly called police. Officers took control of the teenager's computer and arrested the man the next day.'"