BOSTON - UPDATE: Massachusetts state police say they believe the sole surviving Boston bombing suspect is still in the state because of his ties to the area.
SWAT teams in armored vehicles took command of the tense and locked-down streets of Boston and its suburbs Friday in an all-out hunt for the surviving Boston Marathon bombing suspect after his older brother died in a desperate getaway attempt.
Law enforcement officials and family members identify the suspects as 19-year-old college student Dzhokhar Tsarnaev and 26-year-old Tamerlan Tsarnaev.
Police say the brothers shot and killed an MIT policeman, severely wounded another officer and hurled explosives at police during a furious gun battle and car chase. They say Dzokhar Tsarnaev slipped through officers' fingers in a hail of bullets, running over his wounded brother as he drove off.
Authorities believe Dzokhar Tsarnaev is on foot and there is no indication he has a vehicle.
The suspects' clashes with police began hours after the FBI released photos and videos of them. Monday's bombings killed three people and wounded more than 180 others.
During an afternoon press briefing, Massachusetts State Police Col. Timothy Alben said, "We remain committed to this. We don't have an apprehension but we will have one."
Alben said tactical teams would draw back, but state police will be patrolling Watertown for the next 2-3 days.
Mayor Thomas Menino told reporters, "Boston will stand tall … together we will get through this crisis …"
Meanwhile, sources told ABC News that authorities recovered additional explosive devices during the course of their search for the remaining suspect.
The Red Sox and Bruins announced they have postponed their games while authorities continue their search for the suspect.
No makeup date was announced for the opener of the Red Sox three-game series against the Kansas City Royals scheduled for Friday night at Fenway Park. The Bruins game against the Pittsburgh Penguins at TD Garden was rescheduled for Saturday.
Massachusetts Gov. Deval Patrick said mass transit service is resuming in Boston even though the suspect is still on the lam.
Authorities in Boston had suspended all mass transit and warned close to 1 million people in the entire city and some of its suburbs to stay indoors.
Patrick reminded people to "remain vigilant if you are out."
Police: Brothers spent night in Honda
Massachusetts State Police say the brothers suspected in the Boston Marathon bombings spent the night in a Honda Civic and used it to carjack a Mercedes SUV.
Police said Friday morning at a Watertown news conference that one of the brothers stayed with the carjacking victim for a few minutes and then let him go.
They say one brother drove away in the Civic , and the other one drove away in the Mercedes.
Police say one then ditched the Civic and reunited with his brother in the Mercedes. Authorities say both suspects were in the Mercedes when they encountered police and hurled explosives at officers.
The Civic was later recovered in Boston. (Note: Police stated earlier that they were searching for a different model. They made the correction later.)
FBI takes computer from NJ sister of bomb suspects
Police in New Jersey say it appears a sister of the Boston Marathon bombing suspects had no contact recently with her brothers.
The FBI removed a computer and other evidence Friday from the home in West New York, N.J., of Ailina Tsarnaeva.
Police identified the woman Friday evening. They say she told agents she hadn't been in contact with her brothers for a long time.
West New York Police Director Michael Indri says the focus of the investigation was to confirm there was no contact. He says he's confident the FBI confirmed that.
The woman told News12 New Jersey and The Star-Ledger newspaper she has no idea what got into her brothers. At the same time, she says she doesn't know if the accusations against them are true.
Classmates: Bomb suspect was on campus this week
Students at the University of Massachusetts Dartmouth tell The Associated Press that Boston Marathon bombing suspect Dzhokhar was on campus this week after the bombings.
Dzhokhar is a student at the school, about an hour's drive south of Boston.
Students say he lived on the third floor of a campus dormitory. Harry Danso, who lives on the same floor, tells the AP he saw him in the dorm hallway this week and Dzhokhar was calm.
Authorities are swarming the campus. The school was evacuated Friday morning amid a manhunt for Tsarnaev.
FBI and SWAT teams have been seen on the campus. A Massachusetts State Police armored truck arrived and two helicopters were seen arriving earlier.
AG, FBI director brief Obama on bombing probe
President Barack Obama has called Massachusetts Gov. Deval Patrick and Boston Mayor Thomas Menino to pledge the government's full support in the investigation into the Boston Marathon bombing.
The White House says Obama expressed his condolences over the death of an MIT police officer killed overnight.
Obama received another briefing Friday afternoon in the Oval Office from Lisa Monaco, his counterterrorism and homeland security adviser.
Earlier Friday, he and Vice President Joe Biden were briefed in the Situation Room by his national security team, including Attorney General Eric Holder and FBI Director Robert Mueller.
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