Boston bombings: a chaotic manhunt for suspects

Gunfire, explosions and a deadly manhunt rocked the usually quiet streets near Boston overnight Thursday into early Friday as police hunted the two suspects in the marathon bombing.

One man was killed in a shootout with police while the second was still at large, with thousands of police searching for him door-to-door, authorities said.

Here is a timeline of the key developments as the night unfolded, according to police and other officials:

-- 10:20 pm Thursday: Police receive information of shots fired at the Massachusetts Institute of Technology in Cambridge, across the Charles River from Boston.

-- 10:30 pm: A policeman is found shot dead in his vehicle in the east campus of the university.

-- Shortly afterwards, police receive reports that two men have hijacked a car in Cambridge, holding the driver of the car hostage for 30 minutes before leaving him unharmed at an area gas station.

-- Police begin searching for the vehicle and found it in Watertown, a suburb near Cambridge.

-- That sets off a chaotic and deadly chase, during which the suspects throw explosives and both sides trade gunfire. One of the suspects is wounded and is later pronounced dead in the hospital. A police officer is also wounded.

-- Police launch a house-by-house search in Watertown, hunting for the remaining fugitive who they warn is "armed and dangerous."

-- 2:00 am Friday: State police send a tweet asking residents of Watertown to "stay in their homes" and "not to answer the door unless it is an identified police officer."

-- 4:00 am: Boston police officially confirm the man killed is one of the two individuals wanted in connection with Monday's marathon bombings, which killed three people and wounded about 180.

"One suspect dead. One at large," Boston police chief Ed Davis wrote in a tweet on his personal account.