“…Public mass shooters are commonly mentally ill or suicidal but most other homicide offenders are not (Ames, 2005;Duncan, 1995;Duwe, 2007;Fox & Levin, 1994;Langman, 2009Langman, , 2015aLankford & Hakim 2011;Lieberman, 2006;Newman & Fox, 2009;Newman et al, 2004;O'Toole, 2000;Rugala, 2003;Vossekuil et al, 2002). Public mass shooters often plan their attacks in advance but other murderers are much more likely to commit crimes of passion or escalation (Langman, 2009;Lankford, 2013;Newman et al, 2004;Vossekuil et al, 2002).…”