Every attack on a computer system leaves a trace behind, no matter what an attacker might to to cover their steps. Also, data can be hidden by an attacker to use later as a back door. Forensics in part looks at uncovering evidence of this activity.
EnCase from Guid-ance Software has been at the vanguard of forensics software for some time - and with good reason.
Now in version 4.14, the solution is a powerful collection of correlation and analysis tools, designed to make the forensic investigator's job as easy as possible.