POSTED: Friday, April 19, 2013 - 5:06am
UPDATED: Friday, April 19, 2013 - 9:32am
CNN — Police sealed off densely populated portions of the Boston metro area early Friday after a violent night of chasing the Boston Marathon terror suspects left one of the men and a police officer dead.
The manhunt effectively shut down a large portion of the nation's fifth-largest metro area.
Developments moved quickly:
-- Police swarmed over a Watertown, Massachusetts, neighborhood looking for the surviving suspect, identified by Boston police as Dzhokhar Tsarnaev, age 19.
-- Several sources told CNN that the dead suspect was Tamerlan Tsarnaev, 26. According to a source briefed on the investigation, the suspects are originally from the Russian Caucasus and had moved to Kazakhstan at a young age before coming to the United States several years ago.
-- Police ordered businesses in the suburb of Watertown and nearby communities to stay closed and told residents to stay inside and answer the door for no one but authorities. Boston authorities advised the same. The city's subway, bus and Amtrak train systems have been shut down. Taxi service across the city was suspended. Every Boston area school is closed.
--The search followed a violent night in which authorities say the men allegedly hurled explosives at pursuers after killing a university police officer, robbing a convenience store and hijacking a car.
"It's jarring," said CNN Belief blog writer Danielle Tumminio, who lives in Watertown.
Oluwaseun Odewale, who lives in Arlington, described his neighborhood as "deathly quiet."
"All my doors are double-locked. It's silent all around, there are no usual sounds of cars, nothing," he said.
Boston's public transit authority sent city buses to Watertown to evacuate residents while bomb experts combed the surroundings for possible explosives.
Police warned Watertown residents to lock their homes and stay away from their windows and doors.
Police officers in full body armor, carrying automatic weapons, flooded the area, traveling the streets in convoys and going door-to-door to track the suspect down.
Massachusetts State Police spokesman Col. Timothy Alben asked residents for patience.
"We need more time," he said. "We're making significant progress up there. But it may take hours to do this."
"This situation is grave." Alben said earlier. "This is a very serious situation that we are dealing with."
The violence began late Thursday with the robbery of a 7/11 convenience store, according to Alben.
Soon after, in Cambridge, across the Charles River from Boston, a Massachusetts Institute of Technology police officer was fatally shot while he sat in his car, the Suffolk County District Attorney's Office said in statement. Police believe the bombing suspects were responsible for the shooting.
The two suspects, according to authorities, then hijacked a car at gunpoint in Cambridge. They released the driver a half-hour later at a gas station.
As police picked up the chase, the car's occupants threw explosives out the windows and shot at officers, according to the district attorney's office.
Officers fired back, wounding one of the men, possibly the person identified by the FBI as suspect No. 1, who is seen in the images released Thursday in a dark cap, sunglasses and wearing a black backpack.
The man died at Beth Israel Hospital. He had bullet wounds and injuries from an explosion, according to officials. The second man apparently escaped on foot.
Richard H. Donohue Jr., 33, a three-year veteran of the transit system police force, was shot and wounded in the incident and taken to a hospital, a transit police spokesman said Friday. The officer's condition was not immediately known.
CNN photographer Gabe Ramirez arrived in Watertown as the chase ended.
"Police were in a standoff with the vehicle just down the hill," Ramirez said. They ordered one suspect out and commanded him to strip down completely naked before putting him in a patrol car, which did not leave the scene.
The man was later released and is not a suspect in the case.
But while the man was being held, FBI agents approached the squad car, and police ordered the man back out of the car. FBI agents questioned him -- still fully undressed -- on the sidewalk.
In an early phase of the lockdown, a man could be seen lying face down on the street with his hands outstretched in front of him and his legs crossed. It is unclear whether this was the man who was arrested and ordered to undress.
Details about the suspects
The men moved to the United States at least a few years ago, according to sources.
Tamerlan Tsarnaev, the older brother, had studied at Bunker Hill Community College and wanted to become an engineer, the source said. He then took a year off to train as a boxer.
The source told CNN's Deborah Feyerick that a posting on a social media site in his name included the comments: "I don't have a single American friend. I don't understand them."
The source added that it should not be assumed that either brother was radicalized because of their Chechen origins.
CNN's Terence Burke, Dave Alsup, Carma Hassan, Jake Tapper, Drew Griffin, Steve Almasy and Chandler Friedman contributed to this report.