This guy doesn't do a great job of distinguishing between viable technologies and schemes based on pseudo-science, but it is the case that law enforcement agencies don't do that great of a job at this sort of thing either. The most interesting project along these lines is written about here:
LINK: http://www.washingtonsblog.com/2013/06/the-next-nsa-spying-shoe-to-drop-artificial-intelligence.html
With the entire Internet and thousands of databases for a brain, the device will be able to respond almost instantaneously to complex questions posed by intelligence analysts. As more and more data is collected—through phone calls, credit card receipts, social networks like Facebook and MySpace, GPS tracks, cell phone geolocation, Internet searches, Amazon book purchases, even E-Z Pass toll records—it may one day be possible to know not just where people are and what they are doing, but what and how they think. The system is so potentially intrusive that at least one researcher has quit, citing concerns over the dangers in placing such a powerful weapon in the hands of a top-secret agency with little accountability. Known as Aquaint, which stands for “Advanced QUestion Answering for INTelligence” [which is run by the Intelligence Advanced Research Projects Activity (IARPA)]...