WATERTOWN, Mass. — One of two suspects in the Boston Marathon bombing is dead after the killing of a university officer and a shootout with police, and a massive manhunt is underway for the other, authorities said early Friday.
Residents of Watertown, a Boston suburb, have been advised by police to keep their doors locked and not let anyone in.
"We believe this to be a terrorist," said Boston Police Commissioner Ed David. "We believe this to be a man who's come here to kill people. We need to get him in custody."
The Middlesex district attorney said the two men are suspected of killing a Massachusetts Institute of Technology police officer on campus in Cambridge late Thursday, then stealing a car at gunpoint and later releasing its driver unharmed.
Hours earlier, police had released photos of the marathon bombing suspects and asked for the public's help finding them. A new photo of the suspect on the loose was released later showing him in a grey hoodie sweatshirt. It was taken at a 7-Eleven in Cambridge, just across the Charles River from Boston.
The first images were released hours after President Barack Obama and first lady Michelle Obama attended an interfaith service at a Roman Catholic cathedral in Boston to remember the bombing victims.
Authorities say the suspects threw explosives from the car as police followed it into Watertown. The suspects and police exchanged gunfire, and one of the suspects was critically injured and later died at a hospital while the other escaped.
The FBI said it was working with local authorities to determine what happened.
The MIT shooting on the Cambridge campus Thursday night was followed by reports of gunfire and explosions in Watertown, about 10 miles west of Boston.
The MIT officer had been responding to report of a disturbance Thursday night when he was shot multiple times, according to a statement from the Middlesex district attorney's office and Cambridge police. It said there were no other victims.