The Regional Justice Information System (REJIS) provides a wide variety of county, regional, State, and national criminal justice information to its users. REJIS presented to the University City Police Department (Missouri) the concept of DDP, which required the acquisition of a small inhouse computer to be shared by the city administration and the police department, so as to still allow police access to the REJIS computers. Five major benefits are derived from this arrangement. First, the police department is able to retain full access to county, regional, State, and national criminal information files. Second, by using its own computer, the department can run any desired analysis of local criminal activity as often as required and in the format which best meets the department's needs. Third, the city administration does not have to purchase the expensive services of a commercial data processing firm. Fourth, the inhouse computer enables the city to expand automated services into many departments and activities which previously could not justify purchasing automated services. Finally, the arrangement places all responsibility for technical support and computer programming with REJIS. Descriptions are provided of three major packages of computer programs which can give a department detailed local criminal activity analyses.