Using a network of microphones dispersed throughout a city, ShotSpotter triangulates the location of a gunshot by comparing the distance from its point of origin to the three closest microphones. ShotSpotter installs and maintains these systems themselves, renting access to local police departments. Besides real-time surveillance, the proprietary data which ShotSpotter collects is fed into the company’s machine learning dataset and spun off into predictive policing programs which police departments may also subscribe to. Given the fallibility of the system, the data is regularly retrofit by human analysts to substantiate the claims made by police officers in court. Chekhov’s Gun stars a ...