Querying a Trajectories Database About Sex Offenders

To combat against serial Sex Offenders (SOs), recent laws call for the use of the Global PositioningSatellite (GPS) technology to monitor their movements 24 hours a day. In this paper, we suggest the use ofa spatio-temporal database suitable to store the trajectories of such a category of criminals, besidestraditional 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 aninvestigative strategy that takes profit from the availability of the trips of the SOs in the database andimplement it in terms of simple queries. As software platform, the SECONDO DataBase ManagementSystem (DBMS) is adopted, since it offers a data type about moving objects as well as a reach set of spatiotemporaloperators that greatly simplify the management of trajectories. The solution recommended in ourpaper opens the frontier to a new generation of software applications, much more effective than thosecurrently used by several criminal investigation departments all over the world, because it keeps togetherthe two components that fully describe any criminal event, namely: space and time.