For any crime to be committed, an intersection must have occurred in both time and place between the offender and the victim. Environmental criminology and the routine activity approach provide a general framework to explain how this intersection occurs. By "inverting" research that has focused on relating crime places to offender residences, locations of a series of crimes can be used to determine where an offender may reside. The probable spatial behavior of the offender can thus be derived from information contained in known crime locations, their geographic connections, and characteristics of surrounding areas. By determining the probability of an offender residing in various areas and displaying these results using isopleth or choropleth maps, police efforts to apprehend criminals can be assisted. This investigative approach is known as geographic profiling. Once a geographic profile has been constructed, various criminal investigative strategies can be employed more effectively and efficiently. 28 references and 3 figures