One was a boxer, one a wrestler. One favored alligator shoes and fancy shirts, the other wore jeans, button-ups and T-shirts.
The younger one gathered around him a group of friends so loyal that more than one said they would testify for him, if it came to that.
The older one, who friends and family members said exerted a strong influence on his younger sibling, once told a photographer, "I don't have a single American friend. I don't understand them."
A kaleidoscope of images, adjectives and anecdotes tumbled forth on Friday to describe Tamerlan Tsarnaev, 26, and Dzhokhar Tsarnaev, 19, the two brothers suspected of carrying out the bombings at the Boston Marathon that killed three people and gravely injured scores more.
What no one who knew them could say was why the young men, immigrants of Chechnyan heritage, would set off bombs among innocent people. There was no shortage of theories — commentators speculated about radicalized young Muslims, angry Chechens and a host of other possible explanations. But by the end of the day they were still just theories.
The Tsarnaevs came with their family to the United States almost a decade ago from Kyrgyzstan, after living briefly in the Dagestan region of Russia. Tamerlan, who was killed early Friday morning in a shootout with law enforcement officers, was 15 at the time. Dzhokhar, who was in custody Friday evening, was only 8.
In America, they took up lives familiar to every new immigrant, gradually adapting to a new culture, a new language, new schools and new friends.
Dzhokhar, a handsome teenager with a wry yearbook smile, was liked and respected by his classmates at Cambridge Rindge and Latin School, where celebrities like Ben Affleck and Matt Damon had walked the halls before him. A classmate remembered how elated he seemed on the night of the senior prom. Wearing a black tuxedo and a red bowtie, he was with a date among 40 students who met at a private home before the event to have their photos taken, recalled Sierra Schwartz, 20.
"He was happy to be there, and people were happy he was there," Schwartz said. "He was accepted and very well liked."
A talented wrestler, he was listed as a Greater Boston League Winter All-Star. "He was a smart kid," said Peter Payack, 63, assistant wrestling coach at the school. In 2011, the year he graduated, was awarded a $2,500 scholarship by the city of Cambridge.
But while life seemed easy for Dzhokhar, for Tamerlan it seemed more fraught. A promising boxer, he fought in the Golden Gloves National Tournament in 2009, and he was noticed by a young photographer, Johannes Hirn, who took him as a subject for an essay assignment in a photojournalism class at Boston University. "There are no values anymore," Tamerlan said in the essay, which was later published in Boston University's magazine The Comment. "People can't control themselves."
Anzor Tsarnaev, the brothers' father, who returned to Russia about a year ago, said in a phone interview in Russia that his older son was hoping to become a U.S. citizen — Dzhokhar became a naturalized citizen in 2012, but Tamerlan still held a green card — but that a 2009 domestic violence complaint was standing in his way.
"Because of his girlfriend, he hit her lightly, he was locked up for half an hour," Anzor Tsarnaev said. "There was jealousy there."
The Associated Press reported that Katherine Russell, of North Kingstown, R.I., was married to Tamerlan Tsarnaev. A statement from her family said, "Our daughter has lost her husband today, the father of her child. We cannot begin to comprehend how this horrible tragedy occurred. In the aftermath of the Patriots' Day horror we know that we never really knew Tamerlan Tsarnaev."
Neighbor Paula Gillette, who lives across the street, said Katherine Russell left for college a few years ago and when she came back she would dress in Muslim garb with head coverings and loose, flowing clothing. Gillette said she thought Russell had gone to Suffolk University in Boston. She said she figured Russell met someone and changed her lifestyle.
Gillette said Russell appeared to be living at the house without her husband. While she hadn't seen Russell in a year or more, she had recently seen the child, whom she estimated to be around 2 years old.
Tamerlan Tsarnaev also was interviewed by the FBI in 2011 when a foreign government asked the bureau to determine whether he had extremist ties, the New York Times reported, citing a senior law enforcement official. The Times quoted the official as saying the interview did not produce any "derogatory" information, and the matter was put "to bed."
In Cambridge, where Dzhokhar lived in the third-floor unit of a caramel-colored wood-frame triple-decker on Norfolk Street, the brothers were often seen together. Neighbors said that people were constantly coming and going at the apartment and that they were uncertain who lived there and who was just visiting. Sometimes they saw people from the unit gathering in the back yard. Tamerlan was fond of doing pull-ups on the trellis, they said.
Dzhokhar's uncle, Ruslan Tsarni, 42, said that on the night before he was killed, Tamerlan had called Tsarni's older brother.
"He said to my brother the usual rubbish, talking about God again, that whatever wrong he had done on his behalf, he would like to be forgiven," said Tsarni, who lives in Montgomery Village, Md., outside of Washington. "I guess he knew what he had done."
Both brothers had a substantial presence on social media. On VKontakte, Russia's most popular social media platform, Dzhokhar described his worldview as "Islam" and, asked to identify "the main thing in life," answered "career and money." He listed a series of affinity groups relating to Chechnya, where two wars of independence against Russia were fought after the Soviet Union collapsed, and a verse from the Koran: "Do good, because Allah loves those who do good."