up, and the unexploded devices. clearly there is a lot of ground to cover. the fbi is taking the lead in the investigation. it will do so through the boston joint terrorism task force. this will be a combined federal, state and local effort. it will be an ongoing investigation. it is a criminal investigation that is has the potential, is a potential terrorist investigation. reporter: and they re asking the public for help. anybody who has any information pertaining to this crime, to call reporter: so far no firm suspect in the bombings. but law enforcement sources say they have a number of active leads. they ve issued a be on the lookout bulletin for someone described as a darker skinned or black male with a black backpack and black sweatshirt. that person could be a foreign national with an accent. sources say he tried to gain access to a restricted area before the blast. police are also looking for a
penske truck that tried to gain access to a restricted area. a federal law enforcement official told cnn that both bombs were small. and initial tests show no c-4 or other high-grade explosive material. suggesting the packages used in the attack were code devices. still there s a certain level of sophistication. having made these bombs before, it s not easy. you just can t get it on the internet, make two of these bombs go off fairly closely together. so somebody had some experience. somebody practiced. reporter: sourcesel cnn that one, possiy two, unexploded devices also were found. potential treasure troves of clues about who may have made the bombs. authorities still have no idea whether they this isitr a domesticevt, or a foreign-based event. i m told that it s still too