Black s Law Dictionary the Bible for legal definitions provides several definitions for evidence (Nolan, 1990). One of the definitions reads Testimony, writings, or material objects offered in proof of an alleged fact or proposition. I have to say it is rather refreshing to have a generally straightforward and concise legal definition; generally, I don t equate straightforward and concise with legal well anything. The definition does provide a good launching point for our discussions on how digital information is viewed in the criminal justice system.

Black s definition of evidence as applied to digital evidence can be viewed in two ways. First, we can examine the computer itself as the evidence. This is clearly the case when the computer is the actual instrument of the crime, such as when the physical parts of the computer are used to commit a crime for example, I hit you over the head with a keyboard. Colloquially, most law enforcement investigators and prosecutors will call the computer itself evidence even in cases where information on the computer relates to a given crime. As one investigator told me: Everything seized at a crime scene is evidence until someone tells me it s not. In this sense, when the computer itself is seized at a crime scene or through a warrant, it is considered by many to be evidence.

Building on the view of the computer as evidence, many assert that the information on the computer requires the original computer to view the...