The new frontier in digital evidence

With cell phones ringing everywhere, agencies need to know how to answer this new call of duty

Today, the ring tones and vibrations of cell phones are everywhere — or at least they seem to be.

At the end of 2006, CTIA-The Wireless Association reported 233 million U.S. wireless subscribers, more than 76 percent of the total U.S. population.

While cell phones are a great technological advantage for businesses, the entertainment industry and everyday consumers, they are also an advantage for law enforcement.

In fact, many opportunities exist to use this relatively new form of digital evidence to help solve cases.

Cell phones as evidence

Cell phones and other mobile devices, such as PDAs and cameras, are increasingly being found on suspects and at crime scenes, says Gary Kessler, associate professor and director of the Center for Digital Investigation at Champlain College. And, he says, increasingly they contain information pertinent to a specific event under investigation or intelligence to link individuals to one another.

Stephen Pearson, founder and CEO of the High Tech Crime Institute Inc. (HTCI), which offers computer forensic services and specialized training, explains why cell phones can be especially meaningful to criminal investigations.

He describes three circles of evidence, one inside of another, to form a bull's-eye. The outer circle is where the least evidence is found. A company-owned PC, where most people would not put evidence, is an example in the outer circle.

The next circle has more evidence, and includes home PCs and other often-shared electronics. The inner circle is where the best evidence is found because it is controlled by one individual. Cell phones typically are used by one person; they can be carried around and used anywhere, and never leave a person's sight.

More than five years ago, when Keith Thomas, a cell phone forensics expert with First Advantage's Litigation Consulting Services, started examining cell phones, he says they were used primarily for one person to speak to another. That was all.

Cell phones have gone from being only a means of communication to include extras such as a phone book, Internet access, text messaging, games and more.

"Just about anything that can be done on a home computer now can be done on a cell phone," says Thomas, a former special agent with the Naval Criminal Investigative Service and one of the first members of the NCIS computer investigations and operations squad.

Criminals are taking advantage of cell phone technology in many ways. For example, predators use cell phones to photograph children on playgrounds. Drug dealers take pictures of their couriers so their customers can recognize them when they deliver drugs, and terrorists can activate bombs using cell phones.

Whether a case involves terrorism, homicide, illegal narcotics, stalking, child pornography, harassment, robberies or another crime, a cell phone can link a suspect to a crime. At some crime scenes, criminals aren't only leaving behind fingerprints, DNA and trace evidence; they're leaving their cell phones, too. One officer reports suspects have left their phones in stolen vehicles.

Mistakes first responders should avoid

When first responders enter a crime scene, they know what to do with fingerprints, DNA and trace evidence — they've been trained. When first responders discover a cell phone, they don't always know what to do.

As with any other evidence, first and foremost, evidence handling procedures must be in place for cell phones. If evidence gets lost in the collection process, it's gone. Like a hair that's blown away by the wind, it won't be there when examiners look for it in the laboratory.

Mistakes involving cell phones as evidence often are made in the acquisition process, says Kessler. He suggests seizing the phone and power supply together, if possible, and turning off the phone for evidence preservation.

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