One Boston Bombing Suspect Dead, Another at Large After Chase, Shootout

In the early hours of Friday morning, the fatal shooting of a police officer at the Massachusetts Institute of Technology culminated in a shootout with police in Watertown, Mass., that brought law enforcement face-to-face with the pair of bombing suspects sought by the FBI in the Boston Marathon attack.

According to a press conference with police officials, two men committed an armed carjacking in Cambridge at 10:20 p.m. Thursday night. After reports of shots fired, at 10:30 p.m. an officer was found shot multiple times in his vehicle. He was pronounced dead at the hospital.

Another armed carjacking later took place in which two males kept the victim with them in the car for half an hour before releasing him at a gas station. Police caught up with the SUV and pursued it to Watertown, Mass. During the chase, "several explosive devices" were thrown from the car by the suspects and one officer was seriously injured.

The suspects engaged in a gunfight with police. Suspect No. 1, as labeled in the FBI surveillance photos released earlier in the day, was mortally wounded and taken into custody.

Hospital officials said he died from a combination of a "blast injury to the trunk" from an explosive device and multiple gunshot wounds.

At one point police made a man strip down before taking him into custody and questioning him in a police car before releasing him -- but not before his naked arrest was splashed across the news.

Suspect No. 2, who was wearing the white backward baseball cap in the FBI photos, was captured on surveillance cameras earlier while robbing a 7-Eleven in Cambridge.

"He should be considered armed and dangerous and is a threat to anyone who approaches him," a police official said. "We believe this is a terrorist. We believe this is a man who's come here to kill people."

Police wouldn't release names of the suspects.

They cordoned off a 20-block perimeter and warned residents with a robocall to stay in their homes , lock doors and windows, and not open the door to anyone but a police officer. As the sun rose, all buses and subways came to a standstill and businesses in suspect neighborhoods were asked not to open their doors. Undetonated explosives are said to be littering the route between Cambridge and Watertown.

NBC News reported the two men have international ties, with "overseas military backgrounds" and had been in the U.S. legally for at least a year -- "not American born." NBC's Pete Williams also reported the suspects told the carjacking victim that they were the marathon bombers.

UPDATE: Williams, whose had the most solid sources in the mainstream media through the week's ordeal, reports that the bombers are possibly from Turkey or Chechnya.

UPDATE: The bombers are brothers from Chechnya who had lived in Turkey at one point. The suspect still at large is Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass. His brother, killed in the early-morning confrontation with police, is 20 years old. They reportedly were "not unfamiliar to the FBI."

UPDATE: Tsarnaev was a recipient of a $2,500 scholarship from the city of Cambridge in 2011, the city he wreaked havoc on overnight. "City officials gratefully acknowledge the generous contribution of the many citizens of Cambridge who make this special opportunity possible," said the announcement.

UPDATE (8 a.m.): Tamerlan Tzarnaev, the suspect killed, was reportedly 26 and born in Russia and has been a legal permanent resident since 2007. The younger brother was born in Kyrgyzstan, according to NBC, or Chechnya, according to Russian media. A Russian journalist reported both attended school in Dagestan, which neighbors Chechnya and also has an Islamist extremist insurgency, before coming to the U.S. CNN reported that the brothers stopped in Kazakhstan, not Turkey, before coming to the U.S.

UPDATE (9 a.m.): According to a high school friend who called into CNN, Dzhokhar Tsarnaev attends University of Massachusetts Amherst and works as a lifeguard at Harvard University.

UPDATE (9:20 a.m.): The uncle of the suspects, who said they grew up in Kyrgyzstan, said his nephew called to ask for forgiveness. "It's crazy, it's not possible, I can't believe it," he said. The father calls his on-the-lam son "a true angel" and told Russia's Interfax news agency he believes his sons were "framed."