By its very nature, law enforcement is an information-rich activity. The information activities of law enforcement can be broken into three categories.
Gathering and analyzing information to determine that a law has been violated;
Gathering and analyzing information to determine the identity of the person or persons responsible for a violation of law; and
Gathering and analyzing information to enable a legal showing in court that the person or persons identified in fact were guilty of the violation.
All of these gathering and analysis activities have been altered in basic ways by functional advancements in the technologies that have become available for collecting, storing, and manipulating data.
In actual practice, these categories can overlap or the activities in each category can occur in several temporal sequences. When a police officer observes someone breaking a law, the officer is determining that a law has been violated, gathering information about who broke the law (presumably the person he or she is observing), and gaining evidence that may be introduced in court (the testimony of the officer).
The essential difference between these categories is the locus or subject about which the information is gathered. In the first category concerning the breaking of a law, the locus of information is the event or activity. In the second sort of activity, the locus is the determination of an individual or set of individuals involved in the activity. In the third category, information associated with categories one and two are combined in an attempt to link the two in a provable way.
Although activities in the first category usually precede those in the second, this is not always the case. Law enforcement authorities have been known to start with “suspicious people” and then seek to discover what laws they might have broken, might be breaking, or might be planning to break. This is one of the rationales for certain kinds of undercover activity and is frequently regarded as more controversial.
These distinctions are important because they help to differentiate cases that generate concern about invasions of privacy from those that involve less controversial uses of the state’s investigatory power.