The two suspects in the Boston Marathon bombings are ethnic Chechen brothers who spent much of their lives away from the breakaway Russian republic and showed few signs of radicalism in the United States, friends and relatives say.

Much is still unknown about Dzhokhar and Tamerlan Tsarnaev, Cambridge residents identified by a national security official as suspects in the twin bombings that killed three people and wounded 176 on Monday.

Tamerlan, 26, who dreamed of Olympic boxing glory, was killed in a shootout late on Thursday. Dzhokhar, 19, described as a low-profile student in high school, was the target of a massive manhunt on Friday.

The men’s uncle, Ruslan Tsarni, said he had not spoken with them since 2009 and urged Dzhokhar to turn himself in.

“He put a shame on our family. He put a shame on the entire Chechen ethnicity,” Tsarni said outside his home in suburban Washington.

Asked what was behind the attack, Tsarni said: “I say what I think what’s behind it – being losers. Not being able to settle themselves and thereby hating everyone who did.”

Dzhokhar said on his page on VK, a Russian-language social media site, that he went to primary school in Makhachkala, the capital of Dagestan, a province in Russia’s Caucasus region that borders Chechnya.

He graduated in 2011 from Cambridge Rindge & Latin School, a public school near Harvard University in Cambridge. His “World view” is listed as “Islam” and his “personal priority” is “career and money.”

He had enrolled at University of Massachusetts Dartmouth, and a high school classmate, Eric Machado, told CNN that Dzhokhar had shown no “tell-tale signs of malicious behavior.”

“We partied. We hung out. We were good high school friends,” he said.

Machado recalled that Dzhokhar once said something in conversation about terrorism, but there was “no evidence that would lead any of us to believe that he would be capable of this.”

Luke O’Neill, 21, a neighbor in Cambridge, said he had last seen the younger man this past winter. He said the family kept to themselves and he often would see Dzhokhar walking alone.

But although an unidentified former classmate described Dzhokhar to Boston television station WBZ as the “class clown,” his VK page showed links to Islamic websites and others calling for Chechen independence.

DAGESTAN SCHOOL

School officials in Dagestan said the family had left for the United States in March 2002 before after arriving the previous year from Kyrgyzstan as refugees.

“The children – there were four of them – were admitted to the School No. 1,” the headmaster, Emirmagomed Davydov, told Reuters Television. “The whole family arrived together and left together.”

U.S. officials said the brothers were in the United States legally.

Tamerlan, the older brother, had been a part-time accounting student at Bunker Hill Community College. He was enrolled there for three semesters – fall 2006, spring 2007 and fall 2008.

“He wasn’t even close” to getting a degree, said Patricia Brady, a spokeswoman for the college.

Tamerlan devoted himself to boxing. After winning a Golden Gloves bout in nearby Lowell, Massachusetts, in 2004, he told the local newspaper, “I like the USA … America has a lot of jobs.

“That’s something Russia doesn’t have. You have a chance to make money here if you are willing to work.”

But Tamerlan Tsarnaev expressed some frustration with the United States in a 2010 profile in “The Comment” magazine published by Boston University’s School of Communications.

The article quotes Tsarnaev as saying that, although he had lived in the United States for five years, “I don’t have a single American friend. I don’t understand them.”

He neither smoked nor drank. He told the magazine, “God said no alcohol.”