WHAT IS DIGITAL EVIDENCE?
Digital evidence is any stored or transmitted data in binary format that may be useful in a criminal or civil investigation. The binary format is how computers store information and is rendered in bits (either 0s and 1s); binary is used in almost all modern computers and digital devices. Digital evidence can take a very large number of forms and can be found on hard drives, cell phones, mobile storage media, networks, and many other sources. Digital evidence can be involved with any sort of crime, like suspects’ e-mail or cell phone data indicating intent, their locations at the time of a crime, and relationships with the victim or other suspects. Some crimes are solely committed within the digital realm and involves information that is illegal or illegal through transmission or creation, such as:
• Child exploitation material
• Computer intrusion
• Counterfeiting
• Domestic violence, threats, and extortion
• E-mail threats, harassment, and stalking
• Gambling
• Identity and intellectual property theft
• Narcotics
• Online or economic fraud
• Prostitution
• Telecommunication fraud
• Terrorism
In what now seems a dated format, a 3.5″ floppy disk led investigators in 2005 to the “BTK” (for “bind, torture, kill”) serial killer who had eluded police capture since 1974 and claimed the lives of at least 10 victims. Dennis Rader, the BTK killer, sent taunting letters describing details of his killings to police and news media. Despite over 1300 DNA samples being collected, Rader eluded detection for years. One of the communications was sent on a 1.44 MB floppy disk to a local TV station. Metadata (see “In more detail: Data about data”) embedded in a deleted word processing file contained “Christ Lutheran Church” and that the document was last modified by “Dennis”; Rader was President of that church’s council. Additional investigation led to the analysis of DNA evidence from Rader’s daughter, which was a familial association to a DNA sample from under a victim’s fingernails. Although “traditional” forensic science finally associated Rader with the killings, it was digital evidence that made that link possible.
