The absolute first basic point of confirmation...does the number of votes counted EQUAL the number of voters signing the poll registry?
This same bit of information should be the starting point for ALL precincts being challenged; Florida, Colorado, Ohio, Pennsylvania, ALL of them, ANYWHERE.
If the votes counted exceed the number of voters signing to vote, there is a problem. Simple test...
Actually this should be done in all counties where a Democrat holds the position of elections supervisor.