1 Boston Bomber suspect dead: MASSIVE SEARCH FOR SECOND

Boston in lockdown

Residents throughout the Boston area -- including Watertown, Cambridge, Waltham, Newton and Belmont -- have been advised to keep their doors locked and not let anyone in. The Boston Police Department warned residents to "stay home." Vehicles were barred from entering or leaving Watertown.

Public and private schools and universities throughout Boston are closed.

The University of Massachusetts Dartmouth ordered an evacuation of its campus, in response to information that a person being sought in connection with the Boston Marathon bombing is a registered student.

Public transit service in Boston has been suspended. Taxis were suspended in the morning, but were resumed in the afternoon. Amtrak service was also suspended indefinitely between Boston and New York. Peter Pan Bus Lines has suspended service to Boston, and Megabus has canceled buses between Boston and other cities.

"It's completely out of his character," Aaronson said of Dzhokhar's alleged role in the bombings. "Everything about him was wonderful. He was completely outgoing, very engaged, he loved the school. He was grateful not to be in Chechnya."

Dzhokhar was not overtly political or religious, Aaronson says. "He spoke and acted like any other high school kid."

Aaronson says he can't reconcile the young man he knows with the characterizations he's seeing in the media. "I cannot do it," he says. "I mean this from the deepest part of my heart: It's not possible it's the same person. It's just not possible."

Jacob Colbath-Hess, a freshman at Harvard University, was a member of the class of 2012 at Cambridge Rindge and Latin School but first met Tsarnaev in middle school.

"I don't really know how to react to this….he was a funny, sweet, goofy kid," said Colbath-Hess. "It's not something you would expect from someone you know."

Police have identified Tsarnaev's older brother, Tamerlan Tsarnaev, 26, as the other bombing suspect, killed during the manhunt at MIT.

The brothers had been living together on Norfolk Street in Cambridge. An uncle, Ruslan Tsarni of Montgomery Village, Md., told the Associated Press that the men lived together near Boston and have been in the United States for about a decade. They came from the Russian region near Chechnya, which has been plagued by an Islamic insurgency stemming from separatist wars.

Dzhokhar was a wrestler at the Cambridge Rindge and Latin School in Cambridge, Mass. He was named a Greater Boston League Winter All Star in 2011.

Cambridge Rindge and Latin School did not immediately respond to USA TODAY's phone calls. Many Boston-area schools were closed Friday.