Social media images are increasingly appropriated, constructed, and used as evidence. To this end, facial recognition technologies are applied to harness social media images as evidence of people’s identities, movements, and actions. This development transforms visual evidence in terms of which images are constructed as evidence and how and by whom they are constructed as evidence. It also grants access to identifying citizens on an unprecedented scale. This article develops a theoretical framework for understanding how social media images are appropriated as evidence and used as identification through facial recognition technologies. Empirically, the article studies the extensive use of social media images in identifications conducted by state actors and open-source actors, exemplified by joint efforts by the FBI and Sedition Hunters to identify the participants in the Capitol Hill siege (2021). The primary finding of the quantitative analysis is that social media images constitute almost one-third of the images used by the FBI in their identification of the rioters, while the qualitative analysis focuses on FBI’s use of leads from Sedition Hunters and this open-source actor’s key, yet obscure, application of facial recognition technologies.