Boston is saturated with cameras:
Nine cities — Boston, Brookline, Cambridge, Chelsea, Everett, Revere, Quincy, Somerville and Winthrop — are all interconnected, and the system is designed to instantly share surveillance images between the municipalities.
If the bomber(s) took public transportation, there’s a good chance those steps can be retraced through video footage. As of 2012 there were nearly 500 cameras in the subway alone, and more on busses. If they drove, cameras on bridges and tolls could help retrace a perp’s steps leading up to the bomb’s placement.
The cameras are pretty slick and the information on them is available immediately — they transmit data wirelessly via an Internet connection. “Stored video can be easily shared with other [Police Departments] over standard web browsers using a system protected by a basic username and password,” the ACLU says.