There are times when the invasion of privacy is a good thing — like when you’re fighting bad guys. After all, criminals have also benefited from all of those new technologies that we enjoy, using digital tools for everything from defrauding credit cards to powering traditional gambling rings.

But law enforcement officials like Sergeant James Welsh have taken advantage of a host of software products to help uncover these crimes. “You and I have migrated parts of our lives to the address book, criminals are no different,” he says.

Welsh, 42, works with the Westchester County Department of Public Safety in Hawthorne, New York. As a member of the forensic investigations unit, he analyzes computers, laptops, smartphones, memory cards from cameras, and any other type of digital storage unit you can think of. It’s a hot area. When he arrived seven years ago, he worked alone — part-time. Today he manages two other full-timers and a part-timer.

Welsh gets called when one of the 43 local police departments within Westchester County has a search warrant or consent from the victim of a crime.  Once he receives the evidence, he makes a copy, which is called — for all you Law and Order fans — a  forensic image or a bitstream copy. Then, to play it safe, he makes a copy of that to work on. “We only want to touch the original once,” he explains. Next he uses software made by software companies Guidance and Access Data as well as several smaller companies and a host of open-source tools to unlock call logs, analyze address books, and sift through digital documents. A simple smartphone search might take him an hour. In the case of a search warrant for a home or office, he may spend 40-80 hours reviewing digital files of all types. “We always stay within the scope of the search warrant,” he adds.

The Westchester unit is a member of the High Tech Crime Investigation Association, a 3100-member global organization that trains and connects law enforcement and corporate crime investigators. According to a survey the group has published on its website, during the past five years, members have seen the biggest increases in specific types of crime including Internet fraud, identity theft, credit card fraud and the use of technology to commit more traditional offenses like gambling.

This runs counter to one of the largest misperceptions Welsh says people hold about his job. “People think it’s all hackers and computer crimes,” he says. The fact is, any crime can be better covered up — and ultimately better uncovered — with tech.

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