Information for KARNAC is generally to be derived from structured, semi-structured and unstructured databases. This would include information derived from e.g. gun registrations, driver's licences, residential and criminal records, as well as the Internet, newspapers and county records.
For example the system might raise an alert if someone attempted to buy components for bomb making, hired a car and rented a hotel room near the White House.
The system can have profound implications for civil liberties, however events such as the Oklahoma City bombing and the September 11, 2001 Terrorist Attack have indicated the need for a proactive mechanism for anticipating terrorist atrocities. But tests of current systems show that they generate an extraordinary number of false-positive events.