The Crime Pattern Analysis System (CPAS) is the interface between the crime pattern analyst and the mass of data held in the central database. Each crime in the central database is assumed to have some basic kind of geographic reference, and each crime should have a time variable. These are only the two cast iron assumptions about the data. However, it would help if for each incident there was some descriptive data such as type of crime or modus operandi. CPAS is a way of transferring data between the central database and this system. CPAS has been designed to offer access to the following functions: (1) identifying sets of seemingly related crimes; (2) offering powerful mapping facilities to managers interested in resource allocation and policing strategies; and (3) making short-term forecasts of crime risk. CPAS will help the crime pattern analyst spot interesting patterns and do more with CPAS relevant data than is possible without it. 5 figures