HICRC article on the epidemiology of homicide perpetration by children 

Using data from the National Violent Death Reporting System, authors David Hemenway and Sara Solnick examine homicides by children aged 0-14. Nearly 90% of the perpetrators were boys, over 90% were aged 11-14, and most use guns.  The authors created five categories which accounted for over 70% of the events.  These categories include: (1) the Caretaker, a juvenile, often an older brother, is given the responsibility of caring for an infant.  The homicide typically occurred in the residence and blunt force is used (no guns); (2) Impulsive shooting during play, in which the child typically shoots a sibling or friend.  Except for some notation of momentary anger, these cases look much like unintentional firearm fatalities; (3) Robbery, a group of youth are trying to steal money, usually from an adult; (4) Group assault, a group of youth are fighting, usually with other youth; (5) Killing an adult family member,  typically a parent or grandparent.  Creating a typology of events is useful both for understanding the problem and determining solutions. The article appears online in the journal Injury Epidemiology.