Despite widespread media coverage of police use-of-force incidents resulting in serious injury or death, there has been relatively little research conducted on how those decisions are made. The current study is a first step toward investigation of deception in shoot/no-shoot situations. We approach this study from the perspective of perceptual–cognitive expertise, a concept that has been studied in sport for 50 years to determine the cognitive underpinnings behind athletes anticipating their opponents’ actions. Participants watched temporally-occluded video stimuli of actors pulling either a revolver or a wallet from two concealed locations on their body, and then anticipated whether the object was a weapon or a non-weapon. The data were analyzed using signal detection metrics, an approach which results in independent measures of sensitivity and response bias. We found that sensitivity was affected by occlusion point and draw location. When only the initial part of the draw motion was visible (and the object was not yet visible), participants were relatively unbiased in their responses. However, as more of the draw motion was revealed, participants tended to adopt a liberal response bias: they identified the object as a weapon more frequently than as a non-weapon.