Which inquiry checks all files in the NCIC system?

The inquiry that checks all files in the NCIC system is QWA. This type of inquiry is designed to provide a comprehensive view of all NCIC datasets, encompassing various categories such as stolen vehicles, missing persons, and wanted persons. By utilizing QWA, law enforcement officials can efficiently query a wide range of information, ensuring thorough background checks and situational awareness during investigations.

In contrast, the other inquiries serve more specialized purposes and do not cover all files in the system. For instance, EMD (Emergency Message Display) and EMI (Emergency Message Indicator) are focused on specific types of alerts or messages rather than a full sweep of the NCIC database. EMO (Emergency Message Out) similarly deals with messages of an urgent nature but lacks the broad scope associated with QWA. Therefore, QWA is essential for comprehensive information retrieval within the NCIC framework.