The authors explain that as criminals increasingly move from the streets to the computer, law enforcement officers should become adept at tracking criminals on the Internet. The article begins with an explanation of what footprinting entails and then presents a case study in which the technique of footprinting was used to track down an identity theft ring. According to the authors, algorithms can be used to extract information from large spatial databases on the Internet. Using Web sites and queries, investigators can search the Internet for footprints left by criminals. Investigators use bits of known information to direct a query and then continually input information gathered with each query in a step-by-step method of forward propagation. In the case study, the authors selected over 300 Web sites that contained surface-level and deep-level information that had the potential of providing increasingly more specific information about the criminals being tracked. The case involved a woman whose identity was used to open a credit card account. The authors assisted the police department in conducting surface and deep Web searches to find the culprit. The authors list the 10 steps they went through in the footprinting process, including the Web site addresses and the queries they used. 13 References, 1 figure