Computer-related crime includes any criminal activity directly involving a computer. About half the States have enacted laws regarding this type of crime. Computer-related crime is hard to detect. It can involve huge losses and is difficult to prosecute under existing laws. Donn Parker has grouped computer criminals into seven basic types. Perpetrators are motivated by economic, ideological, egocentric, or psychotic factors. Victims are often reluctant to report computer crime because they do not want publicity, they lack confidence in the criminal justice system, or they do not want to admit security problems. Investigators must be familiar with terms and concepts of computers and computer-related crime to be able to obtain adequate evidence. Seizure and collection of evidence must meet the same evidentiary requirements involved in other criminal events. All marking and handling must conform to the agency's policies and procedures. The documentary evidence must also satisfy the best evidence and hearsay rules. Using experts can aid the investigation. Tables list topics for which experts can be useful and the types of experts to use.