Authorities have named one of the two bombing suspects as Dzhokhar Tsarnaev, 19, who had been living in Cambridge, Mass., CBS reports. Authorities initially said the brothers were from Chechnya but that has yet to be confirmed.

He's believed to be the brother of suspect No. 1 who was killed late Thursday night in a gunfight.

Police, who say he's the suspect shown in publicly released photos wearing a white cap backwards, have sealed off Watertown, to facilitate the search for this man, known as suspect No. 2.

Because suspect No. 1 was wearing an explosive device when he was wounded, authorities are warning that Tsarnaev may also be wearing an explosive device.