Police and prosecutors are fashioning a new weapon in their arsenal against criminals: digital evidence. The sight of hard drives, Internet files and e-mails as courtroom evidence is increasingly common. “Digital evidence is becoming a feature of most criminal cases,” said Susan Brenner, professor of law and technology at the University of Dayton School of Law, in an e-mail response for this article. “Everything is moving in this direction.” Digital evidence may play a significant role in the trial of pop superstar Michael Jackson on charges of child molestation…