Querying a Trajectories Database About Sex Offenders

Abstract

To combat against serial Sex Offenders (SOs), recent laws call for the use of the Global Positioning Satellite (GPS) technology to monitor their movements 24 hours a day. In this paper, we suggest the use of a spatio-temporal database suitable to store the trajectories of such a category of criminals, besides traditional data pertinent to the context (i.e., data about their home, their past history of offences, (pending) crimes, and sensible areas). To show the effectiveness of such a kind of database, then we focus on an investigative strategy that takes profit from the availability of the trips of the SOs in the database and implement it in terms of simple queries. As software platform, the SECONDO DataBase Management System (DBMS) is adopted, since it offers a data type about moving objects as well as a reach set of spatiotemporal operators that greatly simplify the management of trajectories. The solution recommended in our paper opens the frontier to a new generation of software applications, much more effective than those currently used by several criminal investigation departments all over the world, because it keeps together the two components that fully describe any criminal event, namely: space and time.