Clearwater, FL --If detectivesin Boston find that key image, that face in the crowd that may eventually lead to an arrest, their investigation could bring them to the Pinellas County Sheriff's Office.

It turns out the department has the nation's largest collection of searchable images anda sophisticated face recognition system to go with it, capable of pairing a photograph with a name and address in just seconds.

The Pinellas County Sheriff's office started building this database back in 2001, and since then it has grown into a national resource that investigators in Boston may eventually need.

Before the blast and before the smoke even cleared, hundreds -- if not thousands -- of surveillance and cell phone images were being collected at the finish line of the Boston Marathon.Those personal mementos arenow potential evidence.

Investigators are scanningthecrowd, "And looking at any and every image that they can," said the Pinellas County Sheriff's Office Systems Analyst Scott McCallum.

The technology to turn that search into an arrest may be right here in the Bay area with The Pinellas County Sheriff's office Face Analysis Comparison Examination System (FACES).It's the nation's largest database, with more 30 million images for facial recognition comparisons.

The software uses a hundred data-points, assigning every face a unique number.If the Boston bomber ever took a driver's license or mug shot photo, that image may already be in the system.

If not, it's still a good way to compare the facial features of any suspects.

"And ultimately conclude or determine that that identity is that same person," said McCallum.

It's not just still images. Video can quickly be captured and converted into a still image for a side-by-side comparison.In one test, it took less than six seconds for animage to get a hit from the Department of Motor Vehicles.

And cameras capturing that data are everywhere these days.

We asked pedestrians walking under a camera in Clearwater how they felt about that.

"I don't like being watched all the time, but if it can catch something like that, it's a good thing," said Robert Lindell.

"In bad situations I think it's a great thing to have." said Pamela Ballance.

The FACES system runs 5,000 images a month - 150 agencies with about 2,000 agents total - feedingand tapping into the huge database.

So far the FBI has notcalled from Boston, but with a clear enough picture to work with, Pinellas County S.O. expects it may hear from them.

"That wouldn't surprise us. We get search requests from all over the nation," said McCallum.

Pinellas County originally started the FACES system with grant in 2001.Since then, other agencies decided it would be more efficient and less expensive to use the system rather than set upand try to start one of their own.

As a result,it's grown into the nation's largest database of images for face recognition.