Update: We're continuing to compile real-time updates of this incident on a Storify here.
Confusion reigned in Watertown, Mass. late Thursday night after a campus police officer was shot and killed at MIT in nearby Cambridge. A carjacking followed by a massive police operation ensued in Watertown, with multiple reports of gunfire and explosions in several locations. At least one suspect is said by police to still be at large, armed and extremely dangerous.
UPDATE: Multiple police sources have stated that the shooters in tonight's incidents are strongly suspected to be the Boston Marathon bombing suspects.
The best place to follow the news as it unfolded: Twitter. Several reporters as well as residents were sending a stream of updates and pictures live from the scene. Herewith, in chronological order, shorn of all speculation and unconfirmed reports, is a curated selection of tweets that helped piece the story together.
Scene on Mt. Auburn in #Watertown. Hearing shots fired. Officer possibly shot.twitpic.com/ckcapp— susantran (@susantran) April 19, 2013
Crashed cop car with all windows shot out in our driveway #mit #boston #shooting twitter.com/AKitz/status/3…— Andrew Kitzenberg (@AKitz) April 19, 2013
A possible explosive device was found, and a bomb squad robot sent in:
police are saying that their cell phones could possible blow up the bomb in the street.police ordered to power down all cell phones.— Michael Skolnik (@MichaelSkolnik) April 19, 2013
Green accord license: 116GC7 involvedin shooting. Crashed cop car windows shot out. 62 laurel #mitshooting #boston twitter.com/AKitz/status/3…— Andrew Kitzenberg (@AKitz) April 19, 2013
Being cleared back to School St. Cops not playing around. "Get the fuck out of here. This is not safe!" Hundreds of officers #MITShooting— Wesley Lowery (@WesleyLowery) April 19, 2013
At one point police officers screamed that they feared IEDs, no explosions where I am but officers here were horrified. #MITShooting— Wesley Lowery (@WesleyLowery) April 19, 2013
At least 30 police cars, maybe more, on residential street in Watertown. Police have guns drawn, trying to set up perimeter.— Seth Mnookin (@sethmnookin) April 19, 2013
.@seankellytv reports someone being taken into custody right now.Handcuffed.Police telling residents to move away— WCVB-TV Boston (@WCVB) April 19, 2013
The resident we spoke to, @akitz, is directly above the shootout. Car crashed into his drive.— Ravi Somaiya (@ravisomaiya) April 19, 2013
All cops headed to new active scene told to power down cell phones.— Seth Mnookin (@sethmnookin) April 19, 2013
police moving to another location.getting ready for "tactical response" to response to movement in a house. #watertown— Michael Skolnik (@MichaelSkolnik) April 19, 2013
FBI on the scene. twitter.com/taylordobbs/st…— Taylor Dobbs (@taylordobbs) April 19, 2013
A dozen officer going into our yard at 62 laurel st. #mitshooting #mit #boston twitter.com/AKitz/status/3…— Andrew Kitzenberg (@AKitz) April 19, 2013
Line of cops walking down Dexter Rd is now well over 100.— Seth Mnookin (@sethmnookin) April 19, 2013
Police stationed in Target and other parking lots. Still hundreds of officers on scene. Helicopters/cruisers everywhere— Wesley Lowery (@WesleyLowery) April 19, 2013
Massive search still going on in Watertown. Much less tense than earlier but huge foot search seemingly underway— Wesley Lowery (@WesleyLowery) April 19, 2013
Still very tense scene here. Police ordering journalists to put hands up. Ordered out of area where people gathered.— Sean Kelly (@SeanKellyTV) April 19, 2013
Boston Police spokeswoman says they do not know if suspects tied to marathon bombing.— Sean Kelly (@SeanKellyTV) April 19, 2013
Scanner and on scene chatter makesclear that still lots of confusion. If this was daytime=total chaos, definite traffic casualties.— Seth Mnookin (@sethmnookin) April 19, 2013
Officer warning me to move back: "There's a guy out here with a rifle. He engaged us..."- @davidwade— WBZ Boston News (@cbsboston) April 19, 2013
Cape Cod SWAT Bear cat (armored truck) just arrived in Watertown.— Brian D'Amico (@brianjdamico) April 19, 2013
FBI agents walked by averted their eyes from cameras; Boston pd looked bemused.— Seth Mnookin (@sethmnookin) April 19, 2013
Police are going to stage a command post. Policeman confirms explosives were involved.— Jess Bidgood (@jessbidgood) April 19, 2013
Likely staging area will be Arsenal Mall. Two suspects accounted for. Explosive devices believe used. Multiple scenes, haven't cleared all.— Seth Mnookin (@sethmnookin) April 19, 2013
State Police: "We have two suspects accounted for in Watertown." Believe explosives were used on police.— Sean Kelly (@SeanKellyTV) April 19, 2013
I know Boston.com is reporting suspect related to Marathon. Response at scene certainly indicates - but I haven't gotten word.— Seth Mnookin (@sethmnookin) April 19, 2013
The police have confirmed that they are looking for the guys from Monday's Boston Marathon Bombing.Guy with white hat still at large.— Michael Skolnik (@MichaelSkolnik) April 19, 2013
"White suspect with grey hoodie should be considered armed and extremely dangerous. Possibly with an assault rifle and explosives." -police— Michael Skolnik (@MichaelSkolnik) April 19, 2013
just stating facts: man whose car was jacked in Cambridge described the two car-jackers to police as "Middle Eastern."— Michael Skolnik (@MichaelSkolnik) April 19, 2013
Police on the scene have stressed from the very beginning that they fear suspect has access to phone-triggered IEDs— Wesley Lowery (@WesleyLowery) April 19, 2013
Bomb squad robot inspecting the back seat of the sedan #mitshooting #mit #boston twitter.com/AKitz/status/3…— Andrew Kitzenberg (@AKitz) April 19, 2013
Police boats in Charles River. Heading toward Watertown. Police urging people to stay inside.— Jonathan Hall (@JHall7news) April 19, 2013
Lots of cops leaving the scene. twitter.com/taylordobbs/st…— Taylor Dobbs (@taylordobbs) April 19, 2013
Significantly less helicopter traffic now. Not sure what, if anything that means. Media/locals hoarded into Target parking lot.— Wesley Lowery (@WesleyLowery) April 19, 2013
Repeat--media should NOT go to Arsenal. Media should stage at Brighton Barracks FOR NOW. That might change but you can wait there— MASS STATE POLICE (@MassStatePolice) April 19, 2013
They are investigating this as possibly related to the Marathon bombing but not confirming a link to it.— Brian D'Amico (@brianjdamico) April 19, 2013
"One more suspect at large. Two accounted for should be revised. One accounted for. One at large." -State Police— Michael Skolnik (@MichaelSkolnik) April 19, 2013
Strong possibility connected to MIT shooting. Suspect apprehended transported to hospital. No comment on condition.— Seth Mnookin (@sethmnookin) April 19, 2013
BREAKING: Steve Cooper: According to law enforcement source: The 2 suspects are the #BostonMarathon suspects the FBI are looking for. #7News— 7News (@7News) April 19, 2013
Bomb squad just arrived on Arsenal St in Watertown.twitter.com/davidwade/stat… - @davidwade— WBZ Boston News (@cbsboston) April 19, 2013
pressure cooker found at scene in Watertown.not sure if it was explosive or just a pressure cooker.— Michael Skolnik (@MichaelSkolnik) April 19, 2013
Finally, a public service announcement: please help charge the phones of these hardworking reporters so they can keep tweeting.
Same for me with iPhone 5 RT @sethmnookin: Anyone at Brighton barracks w/iPhone 4 charger - I could use some juice.— Taylor Dobbs (@taylordobbs) April 19, 2013