"The analysis could directly implicate or eliminate the suspect based on the information recovered, or serve as corroboration or contradiction to a suspect or witnesses statement," said FBI Supervisory Special Agent Sean O'Brien, director of the Rocky Mountain Regional Computer Forensics Lab in Centennial, Colorado.
In the 2010 fiscal year, the regional laboratories conducted 6,564 examinations of everything from hard drives and cell phones to floppy disks and VHS videotapes. During that time examiners combed through 3,086 terabytes of data. (For comparison, just one terabyte is equal to about 1,000 gigabytes.)
The digital deluge can be overwhelming.
"The sheer volume of information investigators request to be analyzed exceeds the capacity of forensic examiners available to analyze the data in the laboratory," O'Brien told ABC News.
When two Roy, Utah, teenagers were arrested last week for allegedly plotting an attack on their high school, their computers were sent to be analyzed at the lab in Salt Lake City, according to FBI spokesperson Deborah Bertram.
The Rocky Mountain Regional Computer Forensics Lab played a key role during the 2009 investigation of Najibullah Zazi, who later pleaded guilty in a plot to trigger bombs on New York City subway trains. Analysts searched for evidence on several computers, helped execute search warrants, and examined surveillance video that showed Zazi buying bomb making ingredients at a beauty supply store.
Golden Age of Surveillance
Law enforcement officials still need a warrant to search your physical property, like a laptop. Privacy advocates, however, worry that information you store in the "cloud" or with service providers (think Gmail, Hotmail) can be accessed by a less-stringent subpoena, a legal document that doesn't require a judge's approval.
"The standards to access to that information are very low," said James Dempsey, vice president for public policy at the Center for Democracy and Technology. "Most people don't realize that."
Dempsey's organization is part of a group called Digital Due Process, made up of privacy advocates and companies including Amazon, Google and Microsoft that want Congress to update the Electronic Privacy Communications Act. The law was enacted in 1986, before service providers had become major players in email and cloud computing.
Dempsey says the law should require the government to get a warrant signed by a judge before accessing information stored by service providers.
"The warrant requirement is in the Constitution.We just have to make it clear that it applies not only to your physical effects, but also to your digital life." Dempsey told ABC News. "This is golden age of surveillance. There is more information available more easily to the government than ever before."