Using an IP spoofing technique—where the intruder impersonates another computer by manipulating the handshake sequence numbers—Mitnick copied and stashed awayon another site at the Web a series of security software tools developed by Shimomura that could aid computer hackers in assaulting other networks. Of course, it took Shimomura some time to reconstruct how Mitnick carried through the assault, what exactly he was after and the damage he did. Incidentally, it was much later in the investigation that suspicion focused on Mitnick, especially after he got overconfident and started leaving clues while indulging in his Internet joyrides. An example: doing a search for 'itni' in New York Times technology correspondent John Markoff's, e-mail.