Persons motivated by a range of ideological beliefs and other individual factors have engaged in acts of mass violence with increasing frequency and lethality. As perpetrators of these attacks arm themselves with high-caliber weapons and high-capacity magazines and use or threaten to use improvised explosive devices (IEDs), it is important to acknowledge that civilians are not the only intended targets of these violent attacks. Perpetrators of recent attacks have also been determined to engage, injure, or kill law enforcement officers and other first responders.