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.

5:10 p.m. Thursday - Investigators and video of two suspects and ask for the public's help in identifying them.

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

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 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 released unharmed at a gas station in Cambridge.

Police soon pursue the carjacked vehicle in Watertown, just west of Cambridge.

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The FBI says brothers Dzhokhar Tsarnaev, left, and Tamerlan Tsarnaev are suspects in the Boston Marathon bombings. Police are still looking for Dzhokhar Tsarnaev, sweeping through a residential area outside Boston. Tamerlan Tsarnaev reportedly died after a shootout with police last night. (Robin Young/The Lowell Sun/AP)

Some kind of explosive devices are thrown from the vehicle in an apparent attempt to stop police. The carjackers and police exchange gunfire. A police officer is seriously injured. One suspect is critically injured and later pronounced dead.

Authorities launch a manhunt for the other suspect.

1 a.m. Friday - Gunshots and explosions are heard in Watertown. Dozens of police officers and FBI agents converge on a Watertown neighborhood.

4:30 a.m. - Massachusetts state and Boston police tell people living in that neighborhood to stay in their homes. They identify the carjackers as the same men suspected in the bombings. Overnight, police also release a photograph of one of the suspects. The image apparently was taken from surveillance video at a convenience store in Cambridge. Authorities initially say the suspects robbed the store but later say they did not.

5:50 a.m.- Authorities urge residents in Watertown, Newton, Waltham, Belmont, Cambridge, Arlington and the Allston-Brighton neighborhoods of Boston to stay indoors. All mass transit is shut down.

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

6:45 a.m. - The Associated Press identifies the surviving Boston bomb suspect as Dzhokhar Tsarnaev, 19, who has been living in Cambridge.

8 a.m. - Boston's police commissioner says all of Boston must stay in their homes as the search for the surviving suspect continues.

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's older brother.

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

10:35 a.m. - The University of Massachusetts Dartmouth says it closed its campus and ordered an evacuation after confirming that Dzhokhar is registered there.

11:30 a.m. - Massachusetts State Police explain that the brothers 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.

12:35 p.m. - State police in Watertown say officers are searching door-to-door but still have not found the bombing suspect.

6 p.m. - Lockdown is lifted in Boston, but manhunt continues. Police say they still haven't found the suspect.

7 p.m. - Gunfire erupts in Watertown. Police converge on a boat parked outside a home, where Dzhokhar has been hiding.

8:45 p.m. - Police announced via Twitter that Dzhokhar is in custody. The manhunt is over.