Report: Marathon bomb suspect in custody
Update: TV channels in Boston are reporting that a marathon bombing suspect captured by police has died in hospital.
Boston Police Chief Ed Davis tweeted: ‘One suspect dead. One at large. Armed and dangerous. White hat suspect at large.’
Police are advising residents to stay indoors and not let anyone into their home as they conduct house-to-house search for the 'white hat suspect' who they describe as "armed and dangerous".
Boston police say the suspects were terrorists, who 'came here to to kill people'.
The Boston Police Commissioner describes the dramatic hunt for the suspects, saying the 'terrorists' threw explosive devices from their SUV during a high-speed car chase through the sleepy town.
The Boston Marathon bombing suspect had earlier been taken into custody, reported The Boston Globe.
Another man reportedly remains on the loose.
"One Marathon bombing suspect has been caught, and another is on the loose in Watertown after a firefight with police, officials said", the Boston Globe tweeted earleir this afternoon.
The Globe has sourced the information to an official with knowledge of the investigation.
"Another remains on the loose in Watertown after a firefight with police. Authorities have established a 20-block perimeter as they search for him," the Globe said in a report online.
Massachusetts State Police have tweeted: "Residents in and around Watertown should stay in their residences. Do NOT answer door unless it is an identified police officer."
Police SWAT teams have sealed off the town, reports say, and television reports show police teams moving through the streets block by block.
Reports say the operation began after a robbery at a gas station was followed by the killing of the police officer on the campus of MIT and a car chase to Watertown.
An FBI agent has told the media that the situation remains extremely dangerous. The Cambridge bomb squad arrived in Watertown shortly after 1:30 a.m. local time.
NBC has reported that explosives and a pressure cooker were found at the scene, according to a tweet by NBC News citing sources.
State police spokesman David Procopio said: "The incident in Watertown did involve what we believe to be explosive devices possibly, potentially, being used against the police officers."
The dramatic development came as chaos again descended upon the Boston area, just days after the marathon bomb which killed three people.
Top US college, the Massachusetts Institute of Technology, warned students a gunman was on campus, after an MIT police officer shot and killed.
There were then reports indicating more shots had been fired and explosions had been witnessed as police were led into a chase into nearby Watertown, reportedly following a car-jacking.
The explosions and gunfire were heard in the Watertown district north of the university. "There were blasts, it could have been grenades," local resident Adam Brown told AFP.
It is not clear if the two incidents are linked or how they are linked to the Boston Marathon bombing.
The MIT is just across the river from Boston and the site of the marathon bombing.
One resident told of 'constant gunfire' between police and two men.
Earlier, Cambridge police said the officer was responding to a report of a disturbance in the area when he was shot and suffered 'multiple wounds'.
He was taken to hospital but died from his injuries.
In a statement, Cambridge police said the officer was responding to a report of a disturbance.
"According to authorities, the officer was found evidencing multiple gunshot wounds," the statement said.
"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."
It comes after two bombs at the city's marathon killed three people and injured 180 on Monday.
At 10:48pm local time, the university's emergency information website sent a message to students.
"Gunshots were reported near Building 32 (Stata) which is currently surrounded by responding agencies," the warning read.
"The area is cordoned off. Please stay clear of area until further notice. Unknown if injuries have occurred.
"Although the situation is considered active and extremely dangerous, an investigation is underway. Updates will be provided at this site when more information becomes available."
A later update added: "Injuries have been reported. The situation is still very active and we ask everyone to stay inside."
