Web Sleuthing / Internet Detectives

Web sleuthing, also called online sleuthing or armchair detective work, is the crowdsourced amateur investigation of crimes and mysteries by online communities, who pool publicly available information to identify suspects, locate missing people or solve puzzles. Researchers describe a spectrum of related practices, with one influential framework distinguishing flagging, investigation, hounding and organised denunciation, and they use a range of labels for the participants, including websleuths, digilantes, cyber-sleuths and keyboard sleuths. It overlaps with, but is narrower than, the broader phenomenon of internet vigilantism.

Reddit is a central venue for the practice, hosting dedicated communities such as the Reddit Bureau of Investigation that bring together hundreds of thousands of members to work on real cases. Academic work emphasises that authority in these spaces is interactionally accomplished, meaning credibility is built thread by thread through community response rather than conferred by credentials. The phenomenon matters because the same crowd dynamics that occasionally help solve cases also misfire badly: amateur investigations have repeatedly misidentified innocent people, spread harmful speculation and obstructed professional inquiries, which is why both Reddit's rules and community etiquette discourage witch-hunting and the sharing of personal information.