< Day Day Up > 


The impartial computer forensics expert who helps during discovery will typically have experience on a wide range of computer hardware and software. It is always beneficial when your case involves hardware and software with which this expert is directly familiar. But fundamental computer design and software implementation is often quite similar from one system to another; and, experience in one application or operating system area is often easily transferable to a new system.

Unlike paper evidence, computer evidence can often exist in many forms, with earlier versions still accessible on a computer disk. Knowing the possibility of their existence, even alternate formats of the same data can be discovered. The discovery process can be served well by a knowledgeable expert identifying more possibilities that can be requested as possibly relevant evidence. In addition, during on-site premises inspections, for cases where computer disks are not actually seized or forensically copied, the forensics expert can more quickly identify places to look, signs to look for, and additional information sources for relevant evidence. These may take the form of earlier versions of data files (memos, spreadsheets) that still exist on the computer’s disk or on backup media, or differently formatted versions of data, either created or treated by other application programs (word processing, spreadsheet, e-mail, timeline, scheduling, or graphic).

Protection of evidence is critical. A knowledgeable computer forensics professional should ensure that a subject computer system is carefully handled to ensure that:

  1. No possible evidence is damaged, destroyed, or otherwise compromised by the procedures used to investigate the computer.

  2. No possible computer virus is introduced to a subject computer during the analysis process.

  3. Extracted and possibly relevant evidence is properly handled and protected from later mechanical or electromagnetic damage.

  4. A continuing chain of custody is established and maintained.

  5. Business operations are affected for a limited amount of time, if at all.

  6. Any client–attorney information that is inadvertently acquired during a forensic exploration is ethically and legally respected and not divulged.[iv]

[iv]Judd Robbins, “An Explanation Of Computer Forensics,” National Forensics Center, 774 Mays Blvd. #10-143, Incline Village, NV 89451, 2001. (©Copyright 2002, National Forensics Center. All rights reserved), 2001.

 < Day Day Up > 

 < Day Day Up > 


The computer forensics specialist should take several careful steps to identify and attempt to retrieve possible evidence that may exist on a subject’s computer system. For example, the following steps should be taken:

  1. Protect the subject computer system during the forensic examination from any possible alteration, damage, data corruption, or virus introduction

  2. Discover all files on the subject system. This includes existing normal files, deleted yet remaining files, hidden files, password-protected files, and encrypted files

  3. Recover all (or as much as possible) of discovered deleted files

  4. Reveal (to the greatest extent possible) the contents of hidden files as well as temporary or swap files used by both the application programs and the operating system

  5. Access (if possible and legally appropriate) the contents of protected or encrypted files

  6. Analyze all possibly relevant data found in special (and typically inaccessible) areas of a disk. This includes but is not limited to what is called unallocated space on a disk (currently unused, but possibly the repository of previous data that is relevant evidence), as well as slack space in a file (the remnant area at the end of a file in the last assigned disk cluster, that is unused by current file data, but once again, may be a possible site for previously created and relevant evidence).

  7. Print out an overall analysis of the subject computer system, as well as a listing of all possibly relevant files and discovered file data.

  8. Provide an opinion of the system layout; the file structures discovered; any discovered data and authorship information; any attempts to hide, delete, protect, and encrypt information; and anything else that has been discovered and appears to be relevant to the overall computer system examination

  9. Provide expert consultation and/or testimony, as required[v]


 < Day Day Up >