© 2013 New York Academy of Sciences. The criminal cases of Anders Breivik, the Norwegian shooter, and Bernard Madoff, the fraudulent American financier, are used as prominent examples of the complexity that courts have to explore when judging the severity and responsibility of felonies performed by different types of psychopaths. I outline the brain circuits subserving morally charged decisions in ordinary citizens and in patients with gross lesions in the same areas, along with singularities in these brain systems that have been detected in psychopaths. These neural signatures, combined with thorough neuropsychological examination, will hopefully improve the diagnoses and prognoses of criminals with dangerous psychopathic traits. In this respect, the profiles of incarcerated members of gangs are used to exemplify and distinguish among typical niches and varieties of psychopathy within criminal organizations. A discussion follows, presenting the complexities of novel research that is increasing the sophistication of these challenging but key intersections between neuroscience and law.