(Image Credit: FBI)

Retail surveillance cameras are doing more than just capturing shoplifters as authorities turn to businesses who keep a digital eye on their storefronts.

This footage played a critical role in helping authorities see video of the two Boston bombing suspects, Tamerlan Tsarnaev, 26, and his brother, Dzhokhar Tsarnaev, 19.

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Video surveillance outside the Lord and Taylor department store near the Boston Marathon Finish Line captured images used by the FBI of the Tsarnaev brothers.

Richard Mellor, vice president of loss prevention with the National Retail Federation, said he has seen retailers help capture everything from bag burglars to car thieves in store parking lots.

And the technology is improving in at least two ways.

First, the ability of video to be transported over long distances has expanded with digital capabilities; that is, "transporting the actual images of what is seen on one side of the camera and who is looking at it," Mellor said.

"Now those images are being transported pretty quickly over thousands of miles to headquarters in retailing where they're able to see images of cities around the U.S. where they have stores. That's a new development over the last five years that has grown leaps and bounds."

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Second, the ability to view an enhanced, clarified image is another technological advance.

"Now the ability to enhance the video, and as we have all seen by first images of the Boston bombing, those images were better and more clearer as the hours passed. So the first images of individual faces, that gets enhanced over a computer system," he said. "Those fuzzy black and white images of people for which we cannot make an identification now have been enhanced to the point they keep refining the image so it's so clear that they can make an identification."

In 2011, authorities used camera footage outside a Safeway grocery store to analyze the shooting of former congresswoman Gabrielle Giffords in Tucson, Ariz.

Mellor said many customers prefer to shop in retail stores with surveillance, despite privacy concerns, if the cameras are in plain view.

"Obviously, there's a prevalence of cameras all over the place and the world," Mellor said. "Unfortunately that has become a necessary thing to do with types of crimes out there."

When asked if retailers would ever take the desire for extra footage "too far," and invade privacy in dressing rooms or bathrooms, Mellor said, "I've lived in the retail world a long time. That is an absolute 'no no'. No leader of loss prevention would permit their people to do that."

Security cameras inside a 7-Eleven also helped clarify information during the tense standoff that led to the death of an MIT campus police officer.

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Police initially reported the brothers had robbed a 7-Eleven in Cambridge, which turned out not to be true.

"There was an incident at a 7-Eleven store yesterday evening in Cambridge, but our local loss prevention asset protection manager was able to review the video tape and ascertain the description of who the robber was," said Margaret Chabris, spokeswoman for 7-Eleven.

The convenience chain company has spent millions of dollars installing a state-of-the-art DVR surveillance camera system in the past year, said Chabris.

Like many retailers, 7-Eleven is glad to help authorities by providing surveillance footage for criminal investigations.

"They have helped solved incidents at our stores and police look to us as a resource to investigate crimes that have nothing to do with 7-Eleven," Chabris said.

Lord and Taylor did not respond to an ABC News request for comment.