Might want to start with the field division of the ATF.
Here's the link to the Seattle division:
https://www.atf.gov/seattle-field-division
If nothing else, they may be able to point you in a better direction as they would know how the NICS checks are done in your state. Where I am, Illinois, we go through a state check called FTIPS which polls the federal database. not every state does this.
If nothing else, its a start.
Good Luck!