Two days after twin bombs ripped through crowds at the Boston Marathon, media outlets were reporting that police had identified a possible suspect thanks to nearby cameras and facial recognition software. What goes into tracking down a bomber? With the remnants of a pressure cooker and hundreds of videos to go by, what will investigators be looking for?
Richard Esposito, co-author of "Bomb Squad: A Year Inside the Nation's Most Exclusive Police Unit" and senior executive producer of the investigative unit at NBC News
Rick Hahn, retired FBI agent and explosives expert
Anil Jain, professor of computer science and engineering at Michigan State University who has worked on a number of government-funded projects dealing with facial recognition and fingerprinting