Could technology help us predict future criminals, or perhaps even future victims? Predictive policing aims to do just that and is increasingly being used in the US. Despite controversy around the prejudices it can reinforce, it is mostly sold as technology that ‘makes policing cheaper’. The software ranges from tools like PredPol, which maps crime by looking at geographies and histories of crime, to Hunchlab which combines historical data of crime with other variables like the weather and Hitachi’s system, featured here. This software, Hitachi Visualization Predictive Crime Analytics (PCA), aims to reduce bias in past crime data by introducing other data sources such as social media. Hitachi’ claims social media data increases accuracy by up to 15%, in particular because of a machine learning technology they teach to look for unusual phrases in what they identify as ‘gang’ social media communications.