Curtis Thompson spent 17 years in prison for 4 rape convictions. He had a history of sexual sadism and was deemed highly likely to offend again. Released in 2003, he is now being charged not only with murder but another rape and several other felonies. Prior to his release, prosecutors had sought his commitment to a facility for sexually violent predators because he was highly likely to offend again, but "a King County jury was swayed by his attorney's arguments that he had been a model prisoner and developed good relationships with women who worked for the Department of Corrections." (The Seattle Times, 8/22/06)
Most of us would love to believe that we can tell when someone is sincere, and when they are lying. In fact, the vast majority of us are not--our judgement is about as good as a guess. However, a small percentage of us are indeed very good at deceiving others. Thompson apparently is one.
Dr. Robert Hare has conducted research and written extensively on people he describes as psychopaths. See this page for a listing of his more recent writings.
Hare "points out that among the most devastating features of psychopathy are a callous disregard for the rights of others and a propensity for predatory and violent behaviors. Without remorse, psychopaths charm and exploit others for their own gain. They lack empathy and a sense of responsibility, and they manipulate, lie and con others with no regard for anyone's feelings." http://www.crimelibrary.com/criminal_mind/psychology/robert_hare/3.html
As well as no regard for anyone's safety.
I believe it's important to cultivate people-reading skills, and that takes time and education. However, if we're to have a safer society we need those who decide the fate of violent offenders to understand the manipulations used by them. And for the rest of us, too, so we can become more adept at dealing with those who mean us harm.