The FBI released video and photos Thursday of two suspects in the Boston Marathon bombings who were seen carrying backpacks and walking casually among spectators shortly before the blasts.
Officials hope that publicizing the images, culled from a trove of digital information, will help them identify and apprehend the two men, who were described by Richard DesLauriers, special agent in charge of the FBI's Boston division, as "armed and extremely dangerous."
DesLauriers told a Boston news conference that had investigators first identified one person of interest in the last 24 hours and that breakthrough led to a second. He appealed for the public's help in identifying the men.