Many studies on poaching acknowledge the challenges of wildlife crime detection, but few address the issue. Wildlife crime data may be an inaccurate reflection of the true spatial distribution of events because of low detection rates. The deployment of conservation and law enforcement resources based on biased data can lead to unintended or unproductive outcomes. This study presents a rigorous methodology for estimating wildlife crime detection probabilities and for evaluating different patrol strategies. It illustrates the methodology with a case study in which fake snares were set in a private nature reserve in South Africa. By using an experimental design with a known spatial distribution of fake snares, it was possible to estimate the baseline detection probability by ranger teams and to evaluate three different patrol strategies: directed patrols, patrols with independent observers, and systematic search patterns. Although detection probabilities were generally low, most snares were detected when systematic search strategies were used. This study lays a foundation for understanding the detection probability of poacher snares, and presents a methodology that can be adjusted for other regions and other types of wildlife crimes.