• Examine election documents. Examine poll lists for similar handwriting, giving special attention to names entered at times when voting activity was slow (such as mid-morning and early afternoon) and shortly before the polls closed. • Compare voters’ signatures. Compare signatures on the poll list with corresponding permanent registration cards to identify voters who may not have cast the ballots attributed to them. • Take handwriting exemplars. Take exemplars from each poll official having access to the ballot box, and then compare them with questionable signatures of alleged voters. • Interview voters. Interview the voters whose ballots were used in the scheme to determine whether they voted at the polls, and, if so, under what circumstances.42 4. A Few Cautions Election fraud investigations raise a number of issues not normally encountered in other criminal investigations. Federal prosecutors and investigators should keep the following principles in mind: i. Respect the integrity of the polls. All states define by statute those persons entitled to be inside the polls during an election. Most state poll access laws do not permit federal law enforcement officials access to open polling places. Asking federal investigators to enter open polls risks violating the sovereignty that the states 42 Successful prosecution of those schemes may require the cooperation of a poll official or other “insider.” 96