Citigraf was conceived in 2016, when the Chicago Police Department hired Genetec to solve a surveillance conundrum. Like other large law enforcement organizations around the country, the department had built up such an impressive arsenal of technologies for keeping tabs on citizens that it had reached the point of surveillance overload. To get a clear picture of an emergency in progress, officers often had to bushwhack through dozens of byzantine databases and feeds from far-flung sensors, including gunshot detectors, license plate readers, and public and private security cameras. This process of braiding together strands of information—“multi-intelligence fusion” is the technical term—was becoming too difficult. As one Chicago official put it, echoing a well-worn aphorism in surveillance circles, the city was “data-rich but information-poor.” What investigators needed was a tool that could cut a clean line through the labyrinth. What they needed was automated fusion.