Haha.
Couldn't they check the IP address of the computer and figure it out from there? Also, there's ways to get data off a hard drive no matter what you do. They're playing around with reading the remnants that the lazer gives off, as to read what was on the hard disk. nothing can cover that up.
Hard drives are written on with a electromagnet. When you delete something, it marks that area as open, but the stuff is still there. It just doesn't show up.
EXAMPLE: When I tried to uninstall rise of nations on my old PC, it deleted my entire games folder. D: I was on 2000, so I had to buy a recovery program. (This was a long time ago, before I knew about BL). I got everything back though! :D