This combo of photos released by the FBI early Friday April 19, 2013, shows what the FBI is calling suspects number 1, left, and suspect number 2, right, walking through the crowd in Boston on Monday, April 15, 2013, before the explosions at the Boston Marathon. (AP Photo/FBI)
WATERTOWN, Mass. (AP) -- Two suspects in the Boston Marathon bombing -- identified to The Associated Press as coming from the Russian region near Chechnya -- killed an MIT police officer, injured a transit officer in a firefight and threw explosive devices at police during their getaway attempt in a long night of violence that left one of them dead and another still at large Friday, authorities said.
A law enforcement intelligence bulletin obtained by the AP identified the surviving bomb suspect as Dzhokhar A. Tsarnaev (JOE-khar Tsahr-NEYE-ev), 19, of Cambridge, Mass.
Two law enforcement officials told AP that Tsarnaev and the other suspect who was not immediately identified have been living legally in the U.S. for at least one year.
Russia's North Caucasus region has been plagued by an Islamic insurgency stemming from separatist wars in Chechnya.
AP: Surviving Boston bomb suspect identified as Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass.
WASHINGTON (AP) -- AP sources: Boston bomb suspects from Russia region near Chechnya, lived in US at least 1 year.
(AP) -- The White House says President Barack Obama is being briefed on developments in the investigation into the bombings at the Boston Marathon.
It said in a statement that the president's assistant for homeland security and counterterrorism, Lisa Monaco, was briefing Obama overnight about the news unfolding in Boston and the nearby community of Watertown.
One bombing suspect is dead and a second remains at large.
WATERTOWN, Mass. (AP) -- Police are locking down some neighborhoods in Boston and its western suburbs as they search for the remaining suspect in the marathon bombings.
Authorities urged residents in Watertown, Newton, Waltham, Belmont, Cambridge, Arlington and the Allston-Brighton neighborhoods of Boston to stay indoors. All mass transit was shut down.
At least a quarter of a million people live in those suburbs. Many people in the city of Boston and surrounding areas rely on the Massachusetts Bay Transit Authority to get to work.
The announcement Friday morning comes hours after the killing of one suspect, known as the man in the black hat from marathon surveillance footage. The man in the white hat is on the loose and police are calling him a "terrorist" who came here "to kill."
The FBI is investigating whether the shooting of a campus police officer at the Massachusetts Institute of Technology and gunfire and explosions in a nearby town are related to the Boston Marathon bombings.
A Massachusetts State Police spokesman says one person suspected in the gunfire and explosions has been accounted for and one is at large.
The FBI says it is working with local authorities to determine what happened.
The MIT shooting on the Cambridge campus Thursday night was followed by reports of violence in nearby Watertown, about 10 miles west of Boston.
A state police spokesman said early Friday there is a "strong possibility" the incidents are related.
Cab driver Imran Sais says he heard "a loud boom" while stand