One suspected Boston Marathon bomber was killed early Friday morning and police are hunting the other in Watertown, Mass., after the suspects killed an MIT police officer and wounded a Massachusetts Bay Transportation Authority officer in a wild chase that involved explosives and gunfire, authorities said.

"We believe this to be a terrorist," Boston police Commissioner Ed Davis said. "We believe this to be a man who came here to kill people."

All of Boston, Watertown, Cambridge, Newton, Waltham and Belmont are under a "shelter-in-place" order, with orders for all residents to stay home with doors locked. Do not open the door for anyone other than a licensed law enforcement officer, said Gov. Deval Patrick. The entire MBTA system has been shut down.

SWAT teams, machine guns drawn, were going door-to-door in Watertown. Blood was found behind one building and a police chemist was testing it.

The suspects were identified to The Associated Press as coming from the Russian region near Chechnya, which has been plagued by an Islamic insurgency stemming from separatist wars. A law enforcement intelligence bulletin obtained by the AP identified the surviving bomb suspect as Dzhokhar A. Tsarnaev, a 19-year-old who had been living in Cambridge, just outside Boston, and said he "may be armed and dangerous."

A man who described himself as an uncle, Ruslan Tsarni of Maryland, said the suspects are brothers who have been in the country since 2001.

When his wife showed him the picture of the suspects, he was "shaking."

"Anger, anger, anger. I can't come up with the words," Tsarni said when asked for his response to the terrorist attacks his nephews are accused of. "Unhuman."

A man who described himself as a friend of the suspects, Ahdi Moro, 22, of Watertown, said the two attended Cambridge Rindge & Latin School.

"I was pretty shocked," Moro said. "I would never think anything like that of them. They were good kids."

He said the older brother was a Golden Gloves boxer who is now the father of a 2-year-old and Dzhokhar was an all-star wrestler.

"He was a really quiet kid," Moro said. "He was very popular at school, like, the most popular kid at school. He was a really good-looking kid. He's as American as anybody. He grew up here. He's like a regular Cambridge kid."

He said the older brother was big and tough, and remembered how, on the first day of school, he was "picked on" by three kids - and beat up all three.

"These kids grew up around violence," Moro said. "They were always not scared of anything."

State Police Col. Timothy Alben said the slain man was Suspect No. 1 in Monday's Boston Marathon bombings and the man police are seeking is Suspect No. 2, the man in the white hat seen in images released Thursday by the FBI. The fugitive was described as armed and dangerous, as police set a 20-block perimeter bordered by Arsenal Street and Mount Auburn Avenue. All vehicular traffic has been banned in Watertown.

A new photo of the man thought to be Suspect No. 2, taken from store video in a Cambridge 7-Eleven Friday night, showed him in a gray hoodie sweatshirt.

The chaotic, violent chain of events began with a report of shots fired on the MIT campus at about 10:20 p.m. Friday, according to a narrative released by the Middlesex District Attorney's office.

At 10:30 p.m., an MIT campus police officer was found with multiple gunshot wounds in his vehicle near Vassar and Main streets. He was pronounced dead at Massachusetts General Hospital.

Police then received reports of a carjacking at gunpoint by two men in the area of Third Street in Cambridge. The driver was held in the car by the suspects for about a half hour before he was released unharmed at a gas station on Memorial Drive.

Dozens of police who had converged on the initial MIT scene near Kendall Square after the shooting raced toward Watertown shortly before 1 a.m. Police had tried to pull over a carjacked vehicle, resulting in one suspect shot and 33-year-old MBTA officer Richard H. Donahue Jr. wounded. A manhunt was launched for the suspect who fled, with heavily armed SWAT teams and uniformed cops with their handguns drawn spreading through the area.

One suspect was critically injured in the course of the chase and died in a local hospital.

(c)2013 Boston Herald

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