About 11:30 p.m. Carjacking takes place in Cambridge, apparently by the robbers. MIT officer's injuries said to be life-threatening.
About midnight. Carjacking victim let go at a Cambridge gas station. Police, started hunting for vehicle, still uncertain if suspects could be Boston Marathon bombers. MIT officer reported dead.
Friday, April 19
About 1 a.m. Officers pursued carjacked vehicle into Watertown. Explosives reportedly thrown from fleeing car. Gunfire exchanged between fugitives and police. Transit police officer seriously wounded during pursuit. One suspect fled on foot, and police set up a perimeter around the area.
About 1:25 a.m.: One suspect captured.
1:35 a.m.: Suspect pronounced dead of numerous gunshot wounds at Beth Israel Hospital, as revealed four hours later by hospital official, who said man also had blast wounds.
2 a.m. to 2:30 a.m. FBI released new photographs. Media started to report allegations that the men were the wanted Boston bombers, though accounts initially differed as to whether the captured man had died.
2:45 a.m. to 3:10 a.m. Manhunt in Watertown reportedly zeroed in on a particular house then expanded, with residents told to stay in their homes and let one inside except police officers.
4 a.m. Authorities send out new picture of suspect, then share details of overnight events, including shooting of MIT officer, death of a suspect in a firefight, and manhunt for the other suspect. Waterown residents again told to shelter in place and call 911 to report any suspicious person.
About 6 a.m. All Boston public transit shut down. Shelter in place order expanded to more towns and neighborhoods. SWAT teams entered Watertown homes, checking for fugitive and explosives. Area universities, including MIT and Harvard, suspended classes.
About 6:40 a.m. to 7:45 a.m. Reports began identifying bombing suspects. Associated Press reported they had roots in Chechnya, but had been living in United States, then named the subject of the manhunt as Dzhokhar A. Tsarnaev, 19, of Cambridge. Soon the two men were reported to be brothers, then deceased suspect was named as Tamerlan Tsarnaev, 26.
8 a.m. Shelter-in-place order extended to entire city of Boston by Gov. Deval Patrick.
9:30 a.m.: MIT officer who died identified as Sean Collier, 26, according to Associated Press. Suspects' uncle, Ruslan Tsarni, confirmed their identities.
10:50 a.m. The manhunt was still underway.
Sources: CBS, Atlanta Journal Constitution and Huffington Post.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.