I hope the Taliban didn't count on deleting files to remove the evidence. Even "overwriting" files won't necesarily do it, since most PC disks have spare tracks that are used when the originals fail. This is all hidden from the user. In the US, disks that are sufficiently classified must be physically destroyed with witnesses. I wouldn't expect them to find something so incrminiating as a file called "List_of_Terrorists.doc". Instead, there will probably be e-mail messsages and the like, with return addresses that can be traced.