Since its inception, Hare’s psychopathy construct and the technology it is embodied in, the Psychopathy Checklist (PCL, and later PCL-R), raise criticisms, namely within the scientific community. Despite those, psychopathy and its measuring instrument are widely used in the criminal justice system to identify risk of violence and reoffending. Using the tools provided by the semiotic of scientific texts, the paper will trace a recent episode in the career of this scientific fact. Informed by the sociology of scientific knowledge, more precisely Actor-Network Theory, the paper describes psychopathy’s recent turn towards brain imaging and its attempts at strengthening and renewing its facticity. This paper is neither about defending nor undermining the psychopathy construct and the PCL-R. We contend that documenting the re-making of psychopathy and the PCL-R, and the controversies that permeate them, is a contribution towards making science and technology more accessible. It is especially important in these times of scientificization of public policies. This exploration into the facticity of psychopathy also illustrates the fundamental ontological uncertainty pervading the knowledge that forms the basis of risk calculation.