(Salem, OR) -- The U.S. Department of Justice has sent letters to Secretaries of State across the country demanding information on how voter registration lists are maintained. If they don't reply by Monday, they could face prosecution. Oregon Secretary of State Tobias Read received the letter. He says county clerks maintain voter roles on a daily basis, removing names that shouldn't be on the list. He says all ballots have individual bar codes and signatures are checked to make sure people can only vote once.