Perhaps two concepts are being mixed together:If he is a psychopath, he wasn't nervous then and he isn't nervous now. They know right from wrong, they just don't care.
-remorse
- fear of getting caught
Though full psychopaths are probably not going to be truly remorseful about anything, they could be fearful (nervous) of getting caught and display behavior to demonstrate that.
In short, all full psychopaths would have a lack of true remorse. Not all of this population, however, might display "Doctor Hannibal Lector" type coolness all the time.