I had reason to check on the consequences of misuse of NICS a few years ago and it was potentially a felony under federal law. Credit reporting companies report felony convictions so it's possible they used that avenue. That would be a violation of the federal Fair Credit Reporting Act because it would not be for an allowed purpose; e.g. for obtaining credit or insurance, employment checks, and a few others. Governmental units can access them for some reasons but MAIG would not qualify.