Public demands for greater police accountability, particularly in relation to violence targeting Black and Brown communities, have placed pressure on law enforcement organisations to be more transparent about officers' actions. The implementation of police body-worn cameras (BWCs) has become a popular response. This article examines the embrace of BWCs amidst the wider shift toward evidence-based policing by scrutinising the body of research that evaluates the effects of these technologies. Through an intertextual analysis informed by insights from Critical Race Theory and Science and Technology Studies, we illustrate how the privileging of certain forms of empiricism, particularly randomised controlled trials, evinces what Woolgar and Pawluch describe as ontological gerrymandering. In doing so, the emergent evidence base supporting BWCs as a policing tool constitutively redefines police violence into a narrow conceptualisation rooted in encounters between citizens and police. This analysis examines how these framings, by design, minimise racialised power relations and inequalities. We conclude by reflecting on the implications of these evidence-based claims, arguing that they can direct attention away from - and thus can buttress - the structural conditions and institutions that perpetuate police violence.