Do you think Voldemort has an office somewhere? Does he keep records? Are there dossiers on all of his Death Eaters? Does he keep an accounting of which offenses he's Crucioed them for and which ones are still pending? Does he keep a "to kill" list on paper, and is Harry in the #1 spot? Does he keep a room full of records describing all the atrocities his organization has committed? Does he have a librarian somewhere with a Dark Mark on his arm to organize it all?