CAMBRIDGE, Mass. - UPDATE: State police say officers are going door-to-door, but the Boston Marathon suspect is still on the loose.
Col. Timothy Alben of the Massachusetts State Police said Friday afternoon that officers would go street to street as the manhunt for the bombing suspect continues. Gov. Deval Patrick urged residents to continue staying indoors.
A pair of brothers is suspected of killing a Massachusetts Institute of Technology police officer late Thursday, then stealing a car at gunpoint.
The suspects' clashes with police began hours after the FBI released photos and videos of them. Monday's bombings killed three people and wounded more than 180 others.
Twenty-six-year-old Tamerlan Tsarnaev (tsahr-NY'-ev) was killed overnight. His 19-year-old brother, Dzhokhar (JOH'-kahr) is on the loose.
PREVIOUS REPORT: According to the Associated Press, both men are from the Russian region near Chechnya, an area which is "plagued by an Islamic insurgency stemming from separatist wars." ( http://wfts.tv/11nPTEr )
The Associated Press made contact with the suspects' father who still lives in Russia, and he said his younger son Dzokar is an accomplished second-year medical student.
The father said he spoke to his son yesterday, three days after the Boston Marathon bombings, and everything seemed okay.
"My son is a true angel...he is such an intelligent boy. We expected him to come on holidays here," the father said.
Officials have identified Dzhokar as a terrorist who is armed, dangerous and maybe wearing a suicide vest.
"We believe this a terrorist, we believe this is a man that's come here to kill people," Boston Police Commissioner Ed Davis said.
The shootout happened hours after the FBI released photos and video of Tamerlan wearing a black hat, and Dzhokar in a wearing a white hat late Thursday. ( http://wfts.tv/11m6Mz4 )
In an impromptu press conference Friday morning, a Boston police official said Tamerlan died in a hospital after gunfire was exchanged with officers and explosives were detonated during a large manhunt in Watertown, Massachusetts overnight.
The situation began when a Massachusetts Institute of Technology police officer was shot dead 10:30 p.m. Thursday on the university's Cambridge campus.
Police trailed the suspects to Watertown where the shootout occurred. Suspect number one was pronounced dead at 1:35 Friday morning.
One officer was hurt and is in critical condition, while another MBTA officer was killed in the shooting.
It was not initially clear whether the investigation in Watertown was related to the MIT shooting, but police later confirmed the Marathon Boston suspects were responsible for MIT officer murder.
Police released a new photo of Dzhokar that was taken from a 7-11 in Cambridge, Mass Thursday night.
The 7-11 was robbed shortly before the MIT officer was shot.
A door-to-door search is now underway to find Dzhokhar.
The entire city of Boston is locked down, businesses are closed, classes at school campuses are canceled and mass transit has been shut down.
In a 8:00 a.m. press conference, Massachusetts Gov. Deval Patrick asked the enter city of Boston and the nearby areas of Watertown, Waltham, Newton, Belmont and Cambridge to stay inside and not open their doors to anyone except officers with proper identification.
Police have established a 20-block perimeter around the Dexter Street area of Watertown in an effort to locate Dzhokhar.
The suspects' uncle, Ruslan Tsarni of Montgomery Village, Md., assisted in confirming the suspects' identities and he said the brothers have been in the United States for about a decade. He said the men lived together and Tsarni had no idea about the suspects' plans.
When Tsarni was told that Tamerlan was killed in a gunfight with police, he said "that's what he deserves...they do not even deserve to exist on this earth."
"I am not sympathizing with him," he said during a CBS interview. ( http://wfts.tv/15rrZNA )
In an ABC News interview, Sierra Schwartz, a woman who went to high school with Dzhokhar, said the suspect seemed like a normal kid.
He was shy, but very nice and joked around, she said. She described him as a well-liked honor student and star wrestling athlete who had a lot of friends.
Steven Owens, another high school classmate, said he was a person with a positive attitude who never showed signs of having a vendetta against the United States.
The Monday bombing at the Boston Marathon killed three people and injured at least 170. ( http://wfts.tv/YXSUgh )