What is the primary function of the Interstate Identification Index (III)?

The primary function of the Interstate Identification Index (III) is to maintain records of criminal offenders' aliases and descriptions. The III serves as a national database that allows law enforcement agencies across the United States to quickly access and share information about individuals with criminal histories. This includes essential data such as the various names a person may have used (aliases) and description details like physical characteristics, which are crucial for accurate identification during criminal investigations and law enforcement operations.

This focus on aliases and descriptions helps ensure that law enforcement can properly match individuals to their criminal records, even if they have changed names or used different identities. The other options, while they pertain to different aspects of legal and law enforcement record-keeping, do not align with the specific function of the III, which is centered on criminal history information rather than issues like child custody or traffic violations.