In the aftermath of the Sandy Hook school massacre in 2012, the parents of one 6-year old victim started a foundation to study the causes of homicidal behavior. One result is the discovery that the brains of young, male killers are biologically different from those of other young men. Kent Kiehl, Professor of Psychology at the University of New Mexico, created a mobile MRI scanner to measure the brain density of 500 psychopaths imprisoned for murder and compared the results to those for 3000 other offenders. In his latest study, he looked at young, male offenders.