In the digital age, where every click, purchase, or activity is systematically recorded, it is surprising to discover how difficult it still is to assemble crime data. This paper describes available web-based crime mapping services and discusses some of the key advantages and disadvantages of using this source for both general purposes and scholarly endeavors. Using a research project on crime occurring around train stations as a case study, we illustrate the pitfalls of relying on web-based services compared to requesting crime information directly from law enforcement agencies. We conclude with a few cautionary remarks regarding the use of data services that purport to offer an assemblage of crime data drawn from different jurisdictions.