Police search for a suspect in Watertown, Mass., after the fatal shooting… (Mario Tama, Getty Images )
WATERTOWN, Mass. — With the Boston area jumpy from the deadly marathon bombings, a shooting that killed a police officer at MIT and a nearby carjacking triggered a massive police response.
By early Friday, one suspect was in custody and police had cordoned off an area of the Boston suburb of Watertown, where witnesses reported loud explosions. Police followed the carjacked vehicle to Watertown, according to scanner traffic.
It was unclear whether the incidents had anything to do with Monday's marathon bombings, but hours into the siege police issued an alert on the scanner for a white male wearing a gray hoodie, with black curly hair. "Should be considered armed and extremely dangerous. Possibly armed with an assault rifle and explosives.
"Could have an IED explosive device on him so please use extreme caution. Use extreme caution."
The incidents began about 10:48 p.m. when the Massachusetts Institute of Technology in Cambridge, east of Watertown, issued an emergency alert that a campus police officer had been shot while responding to a disturbance. The shooter was at large, MIT said, and authorities urged everyone to stay inside.
The officer was transported to a hospital, where he was pronounced dead. He had been shot multiple times, the Middlesex County district attorney said in a statement.
Shortly after the shooting, a vehicle was carjacked near campus, according to Henry DiCicco of the Watertown Police Department. Officers chased it to Watertown, where they set up a perimeter and radioed that a suspect had hand grenades and explosives.
One officer worried that cellphones could set off one of the devices.
"Units in the area: Power down all cellphones for fear of explosion. Power down all cellphones," the scanner said.
Ambulances congregated at Arsenal Mall in Watertown as police cars sped by. Police with dogs searched the area. A chopper hovered overhead. Bomb squad vehicles packed the residential neighborhood about four miles from MIT.
A Watertown man who lives about a mile from the cordoned-off area, Aaron Janikian, 27, said he was smoking outside his house when he heard "distinct gunshots" and "a big boom separate from the gunshots."
That was followed, he said, by "more sirens than I've ever heard in my life."
He drove over to see what was happening. FBI, Boston police and SWAT teams had responded.
The alert for a second suspect was issued after a man was taken into custody.
One man was ordered to strip and was taken to a squad car naked.