As computers and networks become more prevalent, investigators are encountering an increasing amount of digital evidence of witness, victim, and criminal activity. Criminals can use the Internet proactively to enhance their current modus operandi (MO) or they can use it reactively to avoid detection and capture. Additionally, the Internet gives offenders greater access to victims, extending their reach from a limited geographical area to victims all around the world. To date, the majority of efforts to apply profiling to crimes involving computers have focused on criminals who target computers. Although these efforts to create inductive profiles give a general overview of past offenders and may be useful for diagnosing and treating associated psychological disorders, they are of limited use in an investigation. They can even be misleading. Criminal profiling can be most useful when little is known about the offender, which is particularly important when offenders use the Internet to conceal their identities and activities. Feeling protected by some level of anonymity, individuals often do things on the Internet that they would only imagine doing in the physical world, and they express thoughts that they would otherwise keep to themselves. Digital evidence may also contain information that can be used to determine the offender's sex, age, occupation, interests, relationship status, and other potentially useful information. When an offender uses the Internet to commit crimes, it can be difficult to pinpoint all of the relevant evidence in the digital vastness. The Internet, however, has many areas that are private and may never show up in a routine search. Developing an understanding of the offender's MO can direct investigators to look for particular traces of digital behavior or to monitor particular virtual areas where the intruder is likely to appear.