John Simek, a computer forensic examiner in Fairfax, Va., recently had a woman come to his office after a divorce proceeding. In court, her husband had presented some mean-spirited e-mails she supposedly sent him from a free Hotmail e-mail account, which led the judge to award the husband sole custody of their children. The woman claimed she’d never seen these messages before, and because the man only presented printouts of the alleged e-mails, Simek knew there was a chance they were fakes. “The bottom line is, it is very easy to dummy up electronic documents,” he says.

Simek asked the ex-husband to bring his computer to his computer forensic laboratory at Sensei Enterprises, and as soon as he looked at it, he knew something was wrong. “We started looking around and we managed to recover these fragments of Hotmail sign-up pages and forms where this guy had created the account he used to send these messages himself,” he says. “With that kind of evidence behind her, the judge reversed quickly that decision.”