The FBI NICS index has 10 prohibitors that prevent/deny any US citizen from buying weapons in the 50 states and its territories. Adding extra categories that will flag an individual if:
1. Visited a foreing country that is known to support terrorist groups.
2. Had any contact with any terrorist group by any means of communication, with supporting evidence for such claim.
3. Had ever been investigated by the fbi for terrorist acts.
4. Preventive anonimous flag if the individual is under any investigation regarding terrorist acts.