All times are approximate:
Thursday, 10:20 p.m. ET: A convenience store near MIT is robbed at gunpoint.
10:30 p.m.: MIT police officer Sean Collier, 26, is found shot multiple times in his vehicle; he is later pronounced dead.
A pair of armed men carjack a Mercedes SUV in Cambridge. They tell the driver they are the marathon bombers, according to a source who spoke with CNN. The driver remains in the vehicle for 30 minutes, then escapes unharmed at a gas station.
Friday, 1 a.m.: Police locate and pursue the SUV in Watertown, just west of Boston.
1:33 a.m.: Explosive devices are thrown from the SUV toward police and gunfire is exchanged. "Suspect No. 1," later identified as 26-year-old Tamerlan Tsarnaev, is killed. Boston transit police officer Richard H. Donohue Jr. is seriously injured, but expected to survive. Surviving suspect flees.
3:45 a.m.: Massachusetts State Police say they will be going door to door in Watertown.
4:30 a.m.: Law enforcement confirms MIT suspects are the Boston Marathon suspects, manhunt continues for "Suspect No 2."
5:01 a.m.: Boston Police release surveillance photo from convenience store robbery and encourage Watertown residents to stay where they are.
6 a.m.: All Boston mass transit shut down. Residents of Watertown, Newtown, Cambridge and other towns west of Boston urged to stay inside.
6 a.m.: Police go door to door in Watertown in search of Suspect No. 2.
7 a.m.: Suspects identified as Tamerlan Tsarnaev, 26, deceased, and Dzhokar A. Tsarnaev, 19; soon afterward, it's confirmed they are brothers originally from Chechnya.
8 a.m.: Boston police commissioner tells all residents to "shelter in place," effectively placing the city on lockdown.
9:32 a.m.: Boston Police tweet this image of Dzhokhar as law enforcement swarm Watertown.
Continue to follow all developments on HLNtv.com's constantly updating live blog.