A common tool in fighting urban terrorism today is the closed-circuit camera system. However, it still takes a tremendous amount of personnel and time to go through all of the available tape. Here is a summary of what was required to put together the narrative of the 2005 bombing in London:

Six days after the attack, police start linking these events together. “By 13 July, the police had strong evidence that Khan, Tanweer, Hussain and Lindsay were the bombers and that they had died in the attacks.” But it was no small feat: Police collected 80,000 CCTV tapes, amounting to hundreds of thousands of hours of footage. The London police brought on some 400 extra officers to help with the grunt of it.

“The scale is enormous,” the narrative concluded.

As Alexis Madrigal writes at The Atlantic, although we have the technology to capture and record every inch of a city in real time, the process very much depends on a human eye to analyze. “Right now, there is no video software that can do this type of analysis,” he writes, “not even in a first-pass way.”

Even so, given the history here, it seems likely that given enough time, the perpetrators of the bombing will be found on camera. Whether the police can connect the thread among all the disparate sources of information is another matter.

In other words, you can collect big data but it still requires humans to make sense of it all. I imagine there is a big opportunity here for someone to create reliable recognition software but this may be a task where humans are simply better.

Wired says the data in Boston is being crowdsourced but the investigation will not:

It is unclear whether law enforcement had overhead cameras mounted in helicopters or other aircraft over the Marathon. (Boston-area cops don’t have spy drones — yet.) But the era of readily-accessible commercial imaging tools provides a twist on the exponential growth of surveillance tech used by law enforcement and homeland security. The data on your phone can become an adjunct to police during the highest-profile investigations.

That isn’t an unfettered benefit to police. The military has found that its explosion of imagery data has stressed its ability to process it, to the point where its futurists are hunting for algorithms that can pre-select images a human analyst sees. Davis requested that any spectator providing media showing the attacks indicate the time they collected the data so police “don’t need to go through the electronic signature.”

Lots of work to do.