Although existing research on the topic is sparse, previous works have shown that there is believed to be a substantial threat of intentional, malicious contamination of the supply chain by criminals and terrorists (Center for Food Safety and Applied Nutrition, 2001; World Health Organization, 2008). Genuine contamination incidents have the potential to result in mass casualties, although empty threats are often enough to generate public fear and lead to considerable economic damage. Although empty threats often appear indistinguishable from those which will result in contamination, it is thought that certain variables identified in perpetrator communications may be able to help separate empty threats from those that will be actualized. This research thus attempts to determine whether a perpetrator’s reported choice of agent could offer functional predictions for the likelihood of actual contamination in future incidents. Findings indicate that chemical agents alone are more likely to be associated with genuine contamination, whereas the claimed use of biological agents alone as well as chemical, biological, and radionuclear agents combined are more often associated with empty threats. The utility of these findings will be discussed, as well as suggestions for future research.