The National Names Index comprises multi-jurisdictional indexed data on criminal histories, missing persons, warrants, domestic violence orders, adverse firearms history and other related information on persons of interest for use by police nationally. It provides an early warning for police by flagging information on those persons who may not be known on local police jurisdictional databases but who have a record in other states or territories. CrimTrac also uses the NNI to initiate national criminal history checking for accredited agencies.