Police were called to Massachusetts Institute of Technology Thursday night (April 18) just before 11 p.m.
An MIT campus police officer responding to a report of a disturbance in the area of Vassar and Main streets was reportedly shot. According to authorities, the officer was found evidencing multiple gunshot wounds. He was transported to the hospital and pronounced deceased.
Authorities launched an immediate investigation into the circumstances of the shooting. There are no other victims. No arrests have been made. The investigation remains ongoing.
Then, around 1 a.m., a police chase began in Watertown, Mass. Chatter on the police scanner revealed confusion on the scene as officers reported gunfire, explosions and chaos at intersection of Laurel and Dexter Street.
Around 2 a.m., Boston Police were setting up perimeter tape across Nichols Avenue.
One suspect was transported to a nearby hospital, and there were mixed reports on a second suspect in custody.
Just before 2:30 a.m., about 50 emergency vehicles, including local and state police, bomb squad and FBI, surrounded one home in Watertown.
Shortly after 3 a.m., CNN released the below image. Not clear if this is suspect #2.
At 3:18 a.m.:
One suspect was in custody and on his way to hospital.
At 3:40 a.m., it was confirmed that these incidents were actions of the Boston Marathon suspects. Suspect #1 on the left is dead after a shootout with police. Suspect #2 is on the run.
Police are telling people not to stop their car for anyone in case of hijacking. Stay indoors.
Just before 4 a.m., a bomb needed to be detonated by police. Residents are being warned.
5:25 a.m.: At a press conference at Beth Israel Hospital, staff stated there were 12 victims from the initial event hospitalized, one in serious condition.
Police say that this man wearing this hoodie is the suspect at large, he is a terrorist and is considered very dangerous.
At 5:46 a.m., all Boston public transportation was shut down.
City of Boston asked businesses to close and nobody to leave home. No vehicle traffic will be allowed in or out of Watertown, and police are asking all to cooperate.
Just before 7 a.m., police released the name of the suspect at large. Surviving Boston bomb suspect identified as Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass.