So, unfortunately, the police are often not politically neutral and usually skew towards a conservative bent - this is also likely explicitly outside their jurisdiction since it involves a federal election (and America has a really dark history of law enforcement interfering with elections) so, charitably, they may have been unable to act even if they wanted to.

The correct authority in this case would be one of these folks I believe (I’m not a Georgia native):

sos.ga.gov/form/stop-voter-fraud

law.georgia.gov/…/election-fraud-complaint-hotlin…

www.eac.gov/…/register-and-vote-in-your-state?fie…

In actuality, it might be best to start by just calling these folks (phone number from the page above).

404-656-2871