Understanding the cognitive, psychological, and emotional aspects of an offender aids in the investigation, apprehension, treatment, and placement within the correctional system. A psychological evaluation of the crime scene, the interaction of the offender and victim, and the location of the homicide can collectively offer insight into the dark and secretive mind of the serial killer. Some offenders—the antisocial personality or psychopath—appear to fit well into the common fabric of society. Other offenders—the disorganized schizophrenic—display their psychopathology in clear and unambiguous ways. Many fall within the continuum of mental disorders. Determining motivation is a complex endeavor. Through a combination of evidence-based science, proven investigative practices, field experience, and a certain degree of intuition, one begins to understand the complexities of the mind of the serial killer.