An account with Dzhokhar Tsarnaev's name on a Russian social media site lists Islam as his world view, "career and money" and his personal priorities and Chechnya as an area of interest.
His father, speaking from Russia, told The Associated Press that he is a second-year medical student and "a true angel."
"He was a nice guy. He was shy," said Sierra Schwartz, who identified herself as a high school friend. "It was almost physically painful to even call him nice now after this absolute tragedy that happened, but at the time, as we knew him, he was funny."
She added that Dzhokhar Tsarnaev never seemed suspicious and that his identification as a suspect in the marathon bombings came as a shock.
Robin Young, who said her nephew was on the wrestling team with him, told NBC News that he was "just a light, airy, curly-haired kid."
"I can't tell you enough what a beautiful young man this was," she said.
The city of Cambridge awarded Dzhokhar Tsarnaev a $2,500 scholarship toward college in 2011, according to The Boston Globe. The scholarships were for students at Cambridge Rindge and Latin School, part of the Cambridge public school system.
Dzhokhar Tsarnaev's brother, who was killed in a firefight with law enforcement, was identified as Tamerlan Tsarnaev, 26, born in Russia. He became a legal permanent resident in 2007, the officials said. He was the suspect in the black hat in the FBI photos.
Tamerlan Tsarnaev boxed in a 2004 tournament as part of Golden Gloves, a charity program, according to The Lowell Sun newspaper. He told the newspaper then: "I like the USA."
He said that his first love was music, and that he played the piano and violin.
"America has a lot of jobs," he said. "That's something Russia doesn't have. You have a chance to make money here if you are willing to work."
Both men were believed to have military experience, and to have entered the country with their family in 2002 or 2003, when the family sought asylum. The nature of the military experience was not clear. Later in the morning, U.S. Army officials told NBC knows that no one matching either name had served in the active-duty Army, or the reserves.