An exploration of the current knowledge on young people who kill: A systematic review

•Risk factors relating to juvenile homicide can develop across a person's life span.•Juvenile homicide offenders tend to be male rather than female.•Juvenile homicide offenders are likely to have violent or criminal family members.•Gang/group membership and access to weapons present a risk of offending.•Further work is required to improve the quality of research in this field.

This exploratory systematic review assessed the quality of primary studies on young people who kill and synthesised the findings regarding the characteristics of these offenders. An electronic search yielded 12,717 hits of papers published between 1989 and 2012. Of these, 8395 duplicates, 3787 irrelevant hits, and 527 publications not meeting the inclusion criteria of the review were excluded (15 publications were added after searching the grey literature), leaving 23 good quality studies. From these, a further seven were removed due to their small sample size (i.e., n < 30), leaving a total of 16 studies reviewed in detail. A search update was carried out on 2 February 2014 and no further studies meeting the inclusion criteria were found. The results indicate that juvenile homicide offenders are a heterogeneous group and the risk factors for juvenile homicide are cumulative and evolve through life. The findings are mixed, but ten risk factors are identified which appear to be consistent for offenders across the studies reviewed. The limitations of the current review are highlighted and recommendations for future research are outlined, with particular consideration given to improving the quality of the literature in this field.