Authorities have shut down the Boston area as they conduct a manhunt for the "white hat" suspect behind the Monday's Boston marathon bombings. The suspects have been identified as brothers Dzhokhar and Tamerlan Tsarnaev.
Local authorities engaged in an armed pursuit of the two men allegedly linked to the deadly bombing at the Boston Marathon, according to a police spokesperson during a press conference early Friday morning.
The first suspect had sustained a gunshot wound during an exchange with police and had subsequently died in the hospital.
The second suspect - pictured with a white baseball cap in FBI photos - remained at large.
Regional authorities and the Federal Bureau of Investigation (FBI) were actively pursuing him. The local transit system has also been suspended as the manhunt continues.
They said the Boston marathon bombing suspects had shot dead a campus security official on the Massachusetts Institute of Technology (MIT) late on Thursday night. The university is located in the town of Cambridge, which lies across the Charles River from Boston.
The two suspects then stole a car at gun point soon after that shooting and fled the scene with its driver still in the car. They freed the motorist at a local gas station, according to police.
In the early hours of Friday morning, authorities began pursuing the stolen car in the neighboring community of Watertown, eight miles (12 kilometers) west of downtown Boston
In the exchange of gunfire, one police officer also sustained a wound. He was later reported to have died.
Authorities have advised residents in Watertown to remain inside and not to answer the door except to indentified police officers.
The Boston metropolitan area has remained on high alert since Monday, when two deadly explosions at the city's annual marathon left three people dead and over 170 other people injured.
While the motive behind the terror attack remains unknown, FBI officials finally released photos of two suspects late Thursday in what they hoped would lead to a turning point in the case.
kms/ipj (AFP, Reuters, dpa)