Police converge on neighborhood outside Boston

A tense night of police activity that left a university officer dead
on campus just days after the Boston Marathon bombings and amid a hunt
for two suspects caused officers to converge on a neighborhood outside
Boston, where residents heard gunfire and explosions. The chaos in
Watertown, about 10 miles west of Boston, occurred just hours after a
Massachusetts Institute of Technology police officer was shot and
killed on campus. It was unclear if the outbursts of violence were
related. No arrests had been made in the officer's fatal shooting, and
a manhunt was on for the shooter. The 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. In
Watertown, witnesses reported hearing multiple gunshots and explosions
at about 1 a.m. Friday. Dozens of police officers and FBI agents were
in the neighborhood and a helicopter circled overhead. 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." Boston cab driver Imran Sais said
he was standing on a street corner at a police barricade across from a
diner when he heard an explosion. "I heard a loud boom and then a
rapid succession of pop, pop, pop," he said. "It sounded like
automatic weapons. And then I heard the second explosion." He said he
could smell something burning and advanced to check it out but area
residents at their windows yelled at him, "Hey, it's gunfire! Don't go
that way!" MIT said right after the 10:30 p.m. shooting that police
were sweeping the campus in Cambridge and urged people to remain
indoors. They urged people urged to stay away from the Stata Building,
a mixed-use building with faculty offices, classrooms and a common
area. Hours later, MIT, which has about 11,000 students, said the
campus was clear but the shooter was still on the loose.