Poisoning expertise and outcomes in malicious contamination incidents

It is often assumed that poisoners and product tamperers are likely to share an interest in or knowledge of poisonous substances. The purpose of this paper is to determine whether perpetrators with existing poison knowledge will choose different contaminating agents than non-experts, as well as whether there is a link between poison expertise and outcomes in malicious contamination cases. Based on their expertise, it is expected that those perpetrators with some form of existing poison knowledge would select more concerning and difficult to obtain agents, and that attacks committed by experts would result in more harm than attacks by non-experts.

A content analysis was conducted on qualitative descriptions of malicious contamination events, with relevant behavioural variables identified as being present or absent for each individual case. Differences between experts and non-experts in agent choice and incident outcome were then explored using descriptive statistics, contingency tables and Mann-Whitney U tests.

Agent choice was found to differ between experts and non-experts, with different agents chosen depending on whether the event was a threat or a genuine contamination incident. However, attacks by poison experts were found to be no more deadly than attacks perpetrated by non-experts.

This research provides the first known analysis comparing agent choice and outcomes in malicious contamination incidents as a factor of perpetrator knowledge. Investigative applications are discussed.