The present study examines the formation of police suspicion and the mental processes and decisions officers make prior to stopping and questioning citizens. Furthermore, the authors include a brief discussion of the outcomes of stops made. The authors use both quantitative and qualitative data drawn from an observational study of police decision making in Savannah, Georgia. The reasons officers gave for becoming suspicious of citizens were coded into four categories: appearance, behavior, time and place, and information. The results do not support the speculation that it is during this prestop stage in the officers’ decision making when major levels of discrimination take place. However, the authors did uncover some stops based on nonbehavioral criteria, which are potentially problematic. The implications of these findings for understanding police decision making during the prestop stage of the decision-making process are discussed.