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      Sequence of events in the Boston Marathon bombing suspect search

      Tamerlan Tsarnaev was killed overnight during a violent confrontation with police

      Key moments related to the search for the Boston Marathon bombing suspects, based on reports from the Middlesex County district attorney, Massachusetts State Police, and Boston police.

      - At 5:10 p.m. Thursday, investigators of the bombings release photographs and video of two suspects. They ask for the public's help in identifying the men.

      - Around 10:20 p.m., shots are fired on the campus of the Massachusetts Institute of Technology in Cambridge, just outside Boston.

      - At 10:30 p.m., an MIT campus police officer who was responding to a disturbance is found shot multiple times in his vehicle, apparently in a confrontation with the Boston Marathon bombing suspects. He is later pronounced dead.

      - Shortly afterward, two armed men reportedly carjack a Mercedes SUV in Cambridge. A man who was in the vehicle is held for about a half hour and then released unharmed at a gas station on Memorial Drive in Cambridge. The suspects reportedly told the carjack victim that they were marathon bombers. State Police say the brothers spent the night in a Honda CRV and used it to carjack the Mercedes SUV.

      - Police soon pursue the carjacked vehicle in Watertown, just west of Cambridge. They say one brother drove away in the Mercedes, the other one drove away in the CRV and later ditched it and reunited with his brother in the Mercedes.

      - Some kind of explosive devices are thrown from the Mercedes in an apparent attempt to stop police. The carjackers and police exchange gunfire. A transit police officer is seriously injured . One suspect, later identified as Suspect No. 1 in the marathon bombings, is critically injured and later pronounced dead.

      - Authorities launch a manhunt for the other suspect.

      - Around 1 a.m. Friday, gunshots and explosions are heard in Watertown, just outside Boston. Dozens of police officers and FBI agents converge on a Watertown neighborhood. A helicopter circles overhead.

      - Around 4:30 a.m., Massachusetts state and Boston police hold a short outdoor news briefing. They tell people living in that section of eastern Watertown to stay in their homes. They identify the carjackers as the same men suspected in the marathon bombings. Overnight, police also release a photograph of a man believed to be Suspect No. 2, apparently taken from store video earlier in the evening at a 7-Eleven convenience store in Cambridge. He is wearing a grey hoodie-style sweatshirt.

      - Around 6:35 a.m., The Associated Press reports that the bomb suspects are from a Russian region near Chechnya and lived in the United States for at least 1 year.

      - Around 6:45 a.m., The Associated Press identifies the surviving Boston bomb suspect as Dzhokhar A. Tsarnaev, 19, who has been living in Cambridge, Mass. NBC Identifies the suspect who was killed as Tamerlan Tsarnaev, 26. ( Read more about the suspects .)

      - Around 8:00 a.m., law enforcement extends shelter in place recommendation to the entire city of Boston. Boston's police commissioner says all of Boston must stay in their homes as the search for the surviving suspect in the marathon bombings continues.

      - Around 8:40 a.m., a U.S. law enforcement official and the uncle of the suspects confirm that the name of the slain suspect is Tamerlan Tsarnaev, Dzhokhar Tsarnaev's older brother. The uncle, Ruslan Tsarni of Montgomery Village, Md., told The Associated Press that the men lived together near Boston and have been in the United States for about a decade.

      - Around 8:40 a.m., law enforcement converged on an apartment in Cambridge believed to be the home of the two suspects.

      - Around 9:10 a.m., the AP reports that the suspects' father says his son , Dzhokhar A. Tsarnaev, is accomplished medical student and `a true angel.'

      - Around 9:50 a.m., the AP reports that the MIT officer said to have been shot and killed by the Boston Marathon bombing suspects has been identified as 26-year-old Sean Collier .

      - Around 10:00 a.m., the University of Massachusetts at Darmouth issued the following statement on its website: â??UMass Dartmouth has learned that a person being sought in connection with the Boston Marathon bombing has been identified as a student registered at UMass Dartmouth. The campus is closed. Individuals on campus should shelter in place unless instructed otherwise. Return to this page for details as they become available.â??

      - Around 10:20 a.m., Connecticut State Police say a gray Honda CRV believed to be linked to Dzhokhar Tsarnaev has been recovered in Boston.

      - Around 10:35 a.m., the University of Massachusetts Dartmouth says it closed its campus and ordered an evacuation after confirming that Dzhokhar Tsarnaev is registered there. The school says it closed the campus "out of an abundance of caution" as the search continued. It issued the following statement: "UMass Dartmouth is closed and is in the process of a controlled evacuation of the campus. Students, staff and faculty have been asked to leave campus in a calm and orderly fashion. This action is in response to information that the person being sought in connection with the Boston Marathon bombing is a registered student. State, local, and campus police are on campus to assist with the evacuation and to conduct a full investigation."

      - Around 11:30 a.m., Massachusetts State Police explain that the brothers suspected in the bombings were in the Honda CRV when they carjacked the Mercedes SUV. For a while, each drove one of the two vehicles, but then ditched the Honda and reunited in the Mercedes.

      - Around 11:40 a.m., In an interview with the media in Maryland, an uncle of the suspects tells Dzhokhar A. Tsarnaev to `Turn yourself in, and ask forgiveness' from the victims. Ruslan Tsarni told the media that his nephews have brought same to his family. Tsarni says he hasn't seen the suspects for several years. (Watch a clip of the interview on NBC News)

      - Around 11:40 a.m., Law enforcement has been at the site of an apartment in Cambridge, believed to be the home of the two suspects, for three hours. Law enforcement has expanded the perimeter around the apartment, moving media back, multiple times. A helicopter has been reportedly circling the area and snipers have been spotted on rooftops.

      12:00 p.m. â?? Yahoo!News reports that the leader of the Russian republic of Chechnya, Ramzan Kadyrov, blames the suspectsâ?? attack on their upbringing in the U.S. "They (the brothers) grew up and studied in the United States and their attitudes and beliefs were formed there," Kadyrov said.

      - Around 12:18 p.m. - NBC reports that police found at least one other device and disabled it Friday morning. Law enforcement may be searching for additional people involved and are looking at the suspects' travel records.

      - Around 12:30 p.m. - Law enforcement briefed the media. Massachusetts Gov. Deval Patrick says the lockdown continues. He says there are continuing developments in the investigation, which they can not share at this time. Timothy Alben, Superintendent of Massachusetts State Police, says there has been no apprehension at this time. Alben says there will be a controlled explosion at a residence on Norfolk Street in Cambridge on Friday afternoon that is believed to be the home of the two suspects.

      Around 12:50 p.m. - The AP reports that Congressman Dutch Ruppersberger, senior Democrat on the House Intelligence Committee, says the suspects had collected pipe bombs, grenades and improvised explosive devices before they confronted police. The Maryland Democrat said, "They clearly amassed a small arsenal of explosives." Ruppersberger said law enforcement and intelligence officials plan to pivot from their search for the surviving suspect to learn whether the brothers had any help or contact from terrorist groups inside or outside the U.S. Ruppersberger said authorities likely will ask Russian officials for evidence in Chechnya and other nearby Russian regions.

      - Around 1:00 p.m. - The AP reports that deceased bombing suspect Tamerlan Tsarnaev traveled to Russia last year and returned to the U.S. six months later. He is believed to have traveled out of John F. Kennedy International Airport in New York.

      - Around 1:10 p.m. - The AP reports that the FBI is at the northern New Jersey home of the sister of the Boston Marathon bombing suspects. They have cordoned off the three-story brick building across the Hudson River from New York City. The woman has told authorities she has not been in frequent touch with her brothers and says she is very upset. The woman says her brothers are smart and great people.

      - Around 2:00 p.m. - The AP reports that Connecticut State Police say they received information that the at-large suspect could be traveling in a green Honda Civic. State police say in a statement issued to the media that the suspect could possibly be in a 1999 Honda with Massachusetts registration number 116-GC7.

      - Around 2:05 p.m. â?? The suspectsâ?? aunt tells the media that she believes the men are innocent. She says she believes the photos shown by the FBI were staged.

      - Around 2:11 p.m. - The AP reports that students at UMass Dartmouth say Dzhokhar Tsarnaev was on campus this week after the bombings. 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 Tsarnaev was calm.

      - Around 2:30 p.m. - The dead suspect, Tamerlan Tsarnaev, and the MIT officer allegedly killed by the brothers have links to the same boxing gym. Bob Covino, who co-founded the Somerville Boxing Club, says Tsarnaev trained at the gym several years ago. Covino says the MIT officer slain by the bombing suspects, Sean Collier, began volunteering at the gym seven or eight months ago. Covino says it's very unlikely that the two men crossed paths at the gym, because he hasn't seen Tsarnaev for several years and Collier only came over recently. Covino says Collier had been helping teach the younger boxers. The officer also set up a website for the gym.

      (Information from the Associated Press was used in this report.)