For almost every reported crime, there’s a paper or digital record of it somewhere, which means hundreds of thousands of data points – number of thefts, break-ins, assaults, and homicides as well as where and when the incidents occurred. The NYPD (and more recently, the LAPD) use COMPSTAT, an accountability management system driven by data.While a lot of this crime data is kept confidential to respect people’s privacy, there’s still plenty of publicly available records.
British scientists have developed a portable microwave scanner to help police identify individuals carrying concealed guns and knives. It is small enough to be used covertly, at some distance from the subject. The device is based around microwave radar technology and is designed to pick up the “reflections” of weapons concealed beneath clothing. from bbc