You can't tell what people you've never met are like by studying the fragmentary evidence of one of their deeds. And cloaking it all in pseudoscientific jargon and Graeco-Roman terminology doesn't make it a science. Sure, there may be certain types of mental illness or criminal behavior that manifest themselves in certain types of crimes, and perhaps the evidence might hint whether it was a crime of passion or an insane pervert as opposed to a very cold and calculating crimiinal, but that's about it.

And whatever truth there might be to the whole concept could certainly be exploited by a clever criminal who knows the drill to delude the profiler and his inflated opinion of his ability to read human nature. For example, a murderer familiar with profiling concepts could leave clues that point to a different type of profile, like making an insurance killing look like a political assassination, or a crime of passion.

In my opinion, profiling is a mechanism used by the police to give their wild-ass guesses the respectability of a scientific technique, and is probably used to allow them to acquire search warrants they could never get on the basis of their evidence.