One suspect in Monday's Boston Marathon bombing is dead after a shootout with police, and the second suspect is in custody after a manhunt.
Here's what we know so far about the two young men.
Police and the FBI have identified the suspect who was taken into custody as 19-year-old Dzhokhar A. Tsarnaev, of Cambridge, Mass. News outlets, including the New York Times, have named the deceased suspect as 26-year-old Tamerlan Tsarnaev, the other man's brother.
They are natives of Chechnya, but their family fled from the conflict there in the early 1990s. They lived in Kazakhstan for a few years before moving to the United States, according to a photo essay about Tamerlan Tsarnaev.
Background on Dzhokhar Tsarnaev:
An FBI bulletin says Dzhokhar Tsarnaev was born on July 22, 1993. His profile on the Russian social network site VKontakte says he graduated in 2011 from Cambridge Ringe and Latin School, a highly regarded high school whose alumni include Ben Affleck, E.E. Cummings, Mat Damon and Patrick Ewing. The profile lists his world view as Islam and his personal priorities as "career and money."
The Vkontakte profile says he attended a school named Makhachkala from 1999 to 2001. He left no strong impression there, good or bad, the school's spokesman told Russia Today, an English-languge Russian news channel. She said the family had four children -- two boys and two girls -- arrived there from Kyrgyzstan and studied at the school from 2001 to March 2002.
He is a registered student at the University of Massachusetts-Dartmouth. The school said in a statement on its website that the campus was being evacuated "in response to information that the person being sought in connection with the Boston Marathon bombing is a registered student."
Background on Tamerlan Tsarnaev:
He appears to have been a boxer, and was the subject of a photo essay while he was a student at Bunker Hill Community College in Boston. The essay, "Will Box for Passport," was taken as he was preparing to compete at the National Gold Gloves Competion and was taking a semester off to train.
The captions offer the following details: He was born in Chechnya and had been living in the United States for five years at the time. But, he said, "I don't have a single American friend, I don't understand them." Still, he talked about potentially being selected for the Olympic team and said he would rather compete for the United States than Russia unless Chechnya became independent.
The AP reported that officials at the community college said he studied there in fall 2006, spring 2007 and fall 2008, and studied accounting.
A report on SpotCrime.com, which aggregates incident reports from police departments, says he was arrested in July 2009 for allegedly assaulting his girlfriend.
He has a daughter who was born two years ago, an aunt told CBC News.
What people who know the pair are saying:
Ruslan Tsarni, an uncle, told the CBS affiliate in Boston that they came to the United States in 2000 or 2001 and had lived in Cambridge since then. "They do not deserve to live on this earth," he said.
Mark Massey, Tamerlan's former trainer at a Boston gym, told the television station that he was a talented boxer and nice guy. Massey said, "He's not the guy I used to know" and said he was "shocked just like everybody else."
Anzor Tsarnaev, the suspects' father, told the AP Dzhokhar Tsarnaev was a second-year medical student and an "intelligent boy." He says, "My son is a true angel."
Pamela Rolan, a Umass-Dartmouth senior who knew Dzhokhar, told the Boston Globe: "He studied. We hung out with me and my friends. I'm in shock."
Larry Aaronson, Dzhokhar's high school history teacher, told Inquirer columnist Trudy Rubin that the young man came from "a war zone deep inside Chechnya," was "a wonderful kid" and "nothing in his character" suggested he could be responsible for such attacks.
Deana Beaulieu, a high school classmate of Dzhokhar, told the AP that you have to "be careful with the quiet ones," and said she didn't initially recognize him.
A sister of the men told the Newark Star-Ledger that she hadn't been in touch with her brothers in several years. She called Dzhokhar "an amazing child."
Maret Tsarnaeva, an aunt, told CBC News: "My nephews cannot be part of this terrible, horrible act that was committed in the streets of Boston. I know these two nephews -- smart boys, good boys -- they have no motive for that. They have no ideas to be going to this kind of act. It's just not the case, it cannot be true."