Boston bombings: How facial recognition can cut investigation time to seconds

After the Boston Marathon bombings, police in the city made a plea for people with cell phone video and pictures to turn over their footage, adding to the hours of surveillance video from nearby businesses. But what would normally take investigators hundreds of hours to review can now take minutes or even seconds, thanks to technology like facial recognition. The software, which can help pick a person out of crowd, looks for differentiating features — from the shape of a mouth to the ridge on a nose to the distance between a pair of eyes.