Ives Potrafka, a forensic examiner with the Center for Computer Forensics, sees a lot of data theft. Those responsible tend to be ex-employees, either starting up a company while employed or going to a competitor and taking trade secrets.

According to Potrafka, when insiders steal corporate data, they tend to do it via noncorporate e-mail accounts or using external storage media.

Potrafka spent four years as a Special Agent, Computer Forensic Examiner, and Internet Investigator in the High Tech Crime Unit in Michigan Attorney General's Office, and served as a law enforcement officer for 24 years. "Certainly, hacks take place. ... Those are the ones that makes the papers," he says. "But it's more common that it's insider-related and employee-related."

Nowadays, Potrafka tends to work for clients in civil actions, though he still works on the occasional criminal case. A lot of his work involves e-mail analysis and keyword searches.

"A few years ago, we did a case for a major banking corporation where the president of the corporation and the majority of the staff, all within a two-to-three day period, resigned and went to another bank," he said. "We got a call on a Saturday from IT at the bank asking us to come look at some computers at the bank on Monday. Rather than wait until Monday, we came in on Saturday night and started looking at them and by Monday morning, we had found out that the president plugged in an external hard drive to his computer two days before he resigned."

The bank's attorneys then filed a legal demand to see that hard drive, Potrafka said. When they received it, they found stolen files.

Encryption can be an issue, but it isn't a common problem. "If a file is truly encrypted, without the key, you're not looking at it," Potrafka said. "But very honestly, we don't see much of it."

Potrafka participated in a homicide investigation several years ago in which he was asked to construct a timeline that showed when a murder victim had been using her computer.

"It was a case where the husband came over and killed his ex-wife," he said. "She had been connected to America Online. And the America Online records showed she was online the entire time, from like 8:00 p.m. or 9:00 p.m. until 7:50 am the next morning, when her son found her deceased. We were asked to look at the computer and show when she was really using it. ...Working with Microsoft and America Online, we were able to show that she stopped using the computer about 10:50 p.m., which is about her estimated time of death. It kind of blew a hole in the husband's defense."