A full scale digital manhunt is underway record setting web traffic jammed FBI dot gov. After they released photos and surveillance video of two suspects in the Boston Marathon bombings. Over the past... See More
A full scale digital manhunt is underway record setting web traffic jammed FBI dot gov. After they released photos and surveillance video of two suspects in the Boston Marathon bombings. Over the past three days investigators have pored over countless clues but one crucial piece of the puzzle reportedly came from this man. Jeff Bauman that severely injured spectator -- ashen face became an iconic image. Appearing on our screens as responders whisked him away. Jeff lost both legs below the knee but his brother told a reporter. When he awoke from surgery while still in the icu -- gave a description of a man he saw moments before the blast putting down a backpack. It may well have -- led investigators to a dramatic breakthrough we begin with tonight. With more here's ABC's chief investigative correspondent Brian Ross in Boston Brian. -- it was an extraordinary moments and the beginning of a massive international manhunt. Federal law enforcement authorities now believe that a team of at least two men carried out the bombings here not a lone wolf but two men. Described tonight as armed and extremely dangerous. They are now the world's most wanted man. Two men in their twenties caught on tape. Suspect number one with a black -- Suspect number two with a white cap worn backwards both wearing backpacks that the FBI believes held the bombs. We initially developed a single person of interest. Not knowing that the individual -- acting alone or in concert with others we obviously worked with extreme purpose to make that determination. Indeed through that process the FBI developed a second -- some suspects. Off to the side of this video runners can be seen heading to the finish line. And time code markers indicate the footage was made about thirteen minutes before the first bomb went off. Their walk is. Very directed. And a little bit intense but not so much that the average person would pick it up in other words it's clear to me there on. A mission. The FBI believes that does not have a photographic evidence that the first explosion is -- the suspect number one. But for suspect number two with the white -- a different story. Suspects who set -- a backpack at the site of the second explosion. Just in front of the -- restaurant. -- second bomb was sent off just twelve seconds after the first. Suspect number two walked away suspect number two what the white -- -- and proceeded west on Boylston street. And that's all we know right now. Officials say they've made the images public now because they need help in connecting the faces of the potential suspects to actual names. But they warn these are dangerous man. No one should attempt to apprehend them except law enforcement. Let reiterate that can't reiterate that caution do not take any action on your own. The still grieving and shell shocked people of Boston seemed eager to know every detail. And to help tonight you saw -- Yes. These are the people from the FBI since her death at the book is this helpful have truly helpful I mean YouTube -- pictures. Of people -- van dams gave me a place that you bloody -- and eat it may hurt innocent people. Makes you think you. -- -- And you IC and a night and I almost don't wanna get in the -- and and you want to focus on the heroes that at this same time. It why why would you do that it. Innocent people. One of the State's former governors and most prominent residents said he was confident. The suspects would be. This is a day of hope and inspiration from that event but also encouraging to see that that the perpetrators of this may well have been identified. And maybe on their way to. Had just to search. There were other new developments today based on some 300 pieces of evidence recovered from the privacy. Some of the components of the bomb. Including this battery and this circuit board were recognized by lobbyists as parts of a toy remote control car. Similar to this one -- on line posted by the manufacturer. The owner of one hobby store outside Boston says FBI agents interviewed him on Wednesday and left little doubt that a remote control unit had been used. -- said it looked like to me that one of the components was a radio receiver. They've -- the response was back on was dead wrong. There are even instructions on the Internet about how to use the components of -- remote control toy car to set off a -- Both from the anarchist cookbook and jihadist sites as well. -- -- -- Was President Obama joining others for an interfaith service -- We -- one Boston. No -- personally. No challenge. Nothing. Can tear down the resilience. In the higher than sitting. And -- people. There is still no indication. Of whether this was an act of foreign or domestic terrorism. But the president vowed on Thursday that whoever was -- they will not escape. They sought to intimidate us. To terrorize us. To shake -- from those values that the -- described the values that make us who we are as Americans. Well it should be pretty clear by now that they pick. At the wrong city to do. -- -- -- Not -- both.
This transcript has been automatically generated and may not be 100% accurate.