SWAT team members in Watertown SWAT team members in Watertown

Boston remains on lockdown after police conducted a manhunt for two suspects of the Boston Marathon bombings early Friday morning, leaving one of the suspects and a police officer dead. CNN has identified the suspects as brothers Tamerlan Tsarnaev, 26, and Dzhokhar Tsarnaev, 19.

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The older brother, Tamerlan, was shot by police and killed after a car chase through the suburb of Watertown, Mass., in which the suspects reportedly threw explosives at trailing officers.

Originally from Chechnya, the brothers moved to the U.S. several years ago. Tamerlan attended Bunker Hill Community College, where he studied engineering. After graduating from Cambridge Rindge and Latin Academy, Dzhokhar enrolled in the University of Massachusetts Dartmouth.That campus, where he is currently a sophomore living on campus, was evacuated late Friday as authorities continued to search for Dzhokhar. "The Boston Marathon tragedy has touched our University in many ways. On Tuesday, we drew strength from a campus vigil that attracted hundreds of people in remembrance of the victims, and today we learned that a suspect is one of our students," UMass Dartmouth Chancellor Dr. Divina Grossman said in a statement. "We closed and evacuated the campus to assure the safety of our students, faculty and staff. The safety of our campus is always our top priority."

Police have instructed Boston residents to lock their homes and stay away from windows and doors while Dzhokhar remains at large. The subway and Amtrak system has been shut down and every Boston area school is closed. Federal, state and local law enforcement are currently going door-to-door in Watertown, Massachusetts State Police spokesman Col. Timothy Alben said.

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The brothers began a crime spree late Thursday night, allegedly robbing a 7/11 convenience store before fatally shooting a Massachusetts Institute of Technology police officer, 26-year-old Sean Collier, in his car. They proceeded to hijack a car at gunpoint, but released the driver half an hour later at a gas station. According to the district attorney's office, police began pursuing the suspects while they threw explosives out the windows and shot at the officers.

Law enforcement fired back, wounding Tamerlan, who later died at Beth Israel Hospital. He reportedly had bullet wounds and injuries from an explosion. A transit system officer, Richard Donohue, was also injured during the incident. Donohue was released from surgery late Friday. His condition has stabilized, according to CBS News, but he remains in critical condition.