The Associated Press has just announced, via Twitter, that the surviving Boston bombing suspect has been identified as Dzhokhar A. Tsarnaev, a 19-year-old from Cambridge, Massachusetts. He is on the loose and believed to be extremely dangerous. NBC’s Pete Williams reports that the other suspect, believed to be Tsarnaev’s Russian-born, 26-year-old brother, Tamerlan Tzarnaev, was gunned down during a shootout with police in Watertown early Friday morning. The brothers are reportedly both legal, permanent residents of the United States. They are thought to be from a Russian region near Chechnya and have been in the United States for at least one year. Police have reportedly arrested a third man, not a suspect, and have him in custody at the Tzarnaev brothers' Norfolk Street home.