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