This is a case study about using WebGIS for fighting crime from a forensics standpoint.When one thinks about GIS for law enforcement, vehicle tracking and messaging immediately comes to mind. Inteligeo provides support for law enforcement in a different manner: it provides information for the forensics examiner.The system became operational in November 2010 and it now has more than 850 themes and 950 data visualization layers, and is available only inside of the Brazilian Federal Police internal network. It started as tool for fighting environmental crime, now it covers a wide variety of subjects such as environmental data, chemical analysis of pesticides, mining operations, public works fraud and legal status of rural properties. We also have a raster data repository and integration with databases from several institutions.The system uses a fully open source database. After a difficult migration from a proprietary database, the data can now be handled not only by the proprietary GIS framework, but also by tools from the open source ecosystem and by our own maintenance tools.During almost four years of operations, some lessons have been learned and the initial strategic plans have changed. We will discuss issues such as what can be outsourced and what has to be made in house, decisions regarding the database, experimenting versus focusing, key features (our) users use most, demonstrating value to internal management.