This study of 21 youthful parricide offenders (YPOs) ages 11-21 examined the relationship between psychopathology, level of psychopathy, and crime scene behaviors, particularly two forms of "body management": (1) "body movement" and (2) "body alteration." Undoing, a form of body alteration reflecting psychological rather than practical needs, for example, to lessen guilt or symbolically reverse the killing, was present in one-third of the sample. The sample shared common characteristics with juvenile parricide offenders overall in that most of them killed one parent, were victims of chronic child abuse, had one or more psychiatric diagnoses (PTSD was most prevalent), used a firearm, and committed the killings at the family home. Unexpectedly, YPOs who were child abuse victims were not more likely to engage in undoing behaviors than non-abused youth, and over half of the youth with undoing behaviors had elevated psychopathy levels. Three-quarters of youth who moved victim bodies following the murders had elevated psychopathy levels. Similarly, all three youth who transported bodies away from the crime scene had elevated psychopathy levels and conduct disorder. None of the youth with psychotic symptoms engaged in undoing behaviors, altered victim bodies, moved bodies either within or away from the home, or had an elevated degree of psychopathy; they also most often killed using bladed weapons, whereas the nonpsychotic youth usually used firearms. Studies examining the influence of mental illness and psychopathy level on parricidal behaviors by youth are scarce, and to our knowledge this is the largest study to date investigating this area.