While technology played a key role in identifying the two Boston Marathon bombing suspects, Boston Police Commissioner Edward Davis admits that the department's facial recognition system did not help in hunting down the attackers.
"The technology came up empty even though both Tsarnaevs' images exist in official databases: Dzhokhar had a Massachusetts driver's license; the brothers had legally immigrated; and Tamerlan had been the subject of some FBI investigation," the police chief tells The Washington Post.
Although the video surveillance was extremely useful in identifying the suspects, as Ars Technica notes, "facial recognition systems can have limited utility when a grainy, low-resolution image captured at a distance from a cellphone camera or surveillance video is compared with a known, high-quality image." According to the San Jose Mercury News, the "FBI is expected to create a face-recognition system next year for members of the Western Identification Network, a consortium of police agencies in California and eight other Western states."
The investigating team had a painstaking and mind-numbing task to identify the bombers and according to the Post, "One agent watched the same segment of video 400 times." "The goal was to construct a timeline of images, following possible suspects as they moved along the sidewalks, building a narrative out of a random jumble of pictures from thousands of different phones and cameras. It took a couple of days, but analysts began to focus on two men in baseball caps who had brought heavy black bags into the crowd near the marathon's finish line but left without those bags," the report says.