They will you in a minute if you stand between them and something they desire, but usually only if they think they can get away with it. So in this case a psychopath would have followed the victim unnoticed to home or to work and planned out an opportune moment to kill him.
The low clearance rates you cite are not a sign of a higher level of psychopaths or sociopaths, but of fear of gang retaliation and the fact that many blacks prefer high crime from other blacks rather than cooperating with white police to put criminals in jail.
They create an environment where it is easier for psycopaths or sociopaths to operate with impunity.
Another thing that happens is the more a sociopath gets away with crimes, the more emboldened they often become.
On the other side, close calls of being caught can make them more wary.