cyber forensics

What is cyber forensics?
     computer forensics , is the application of scientifically proven methods to gather, process, interpret, and to use digital evidence to provide a conclusive description of cyber crime activities.  Cyber forensics also includes the act of making digital data suitable for inclusion into a criminal investigation.
How is it use in an investigation?
     The purpose of computer forensics techniques is to search, preserve and analyse information on computer systems to find potential evidence for a trial.


and I didn't use it before...