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 -- the one their father described as "like an angel" -- 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 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 such as 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," Ms. 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, he was awarded a $2,500 scholarship by the city of Cambridge, an honor granted to only 35 to 40 students a year.
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 Boston University photojournalism class. "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."
And Tamerlan Tsarnaev was interviewed by the FBI in 2011, when a foreign government asked the bureau to determine whether he had extremist ties, according to a senior law enforcement official. Yet Dzhokhar admired and emulated his older brother, some classmates said, to a degree that in hindsight seemed worrisome.
Peter Tean, 21, a high school wrestling teammate, said he thought Dzhokhar's intense interest in rough-and-tumble sports came from a desire to be like his brother. "He's done these violent sports because his brother's a boxer," Mr. Tean said. "He really loves his brother, looks up to him."
Dzhokhar's uncle, Ruslan Tsarni, 42, also spoke of the influence his older brother had over him, saying of Tamerlan in a phone interview, "He could manipulate him."
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. It is a multicultural neighborhood where hardware stores and butcher shops mix with cafes and Brazilian and Portuguese restaurants. Neighbors said 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 backyard. Tamerlan was fond of doing pull-ups on the trellis, they said.
Mr. Tsarni said that on the night before he was killed, Tamerlan had called Mr. 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 Mr. 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 Quran: "Do good, because Allah loves those who do good."
Mr. Tsarnaev, the father, said Tamerlan would take his younger brother to Friday prayer, but dismissed the idea that Dzhokhar had become devout, saying they sometimes caught him smoking cigarettes.
"Dhzokhar listened to Tamerlan, of course; he also listened to us," he said. "From childhood, it was that way. He had his own head on his shoulders; he was a very gifted person. He had a gift of kindness, calmness, fairness -- you understand, goodness? For him to do what they're saying, it doesn't fit him at all; it is not possible. Not at all."
Mr. Tsarnaev said the family had come to the United States fleeing from war. In Kyrgystan, they were part of a Chechen diaspora that dates back to 1943, when Josef Stalin deported most Chechens from their homeland and over concerns they were collaborating with the invading Nazi army. Most returned to Chechnya in the 1950s, after the death of Stalin and lifting of the deportation order, but some stayed.
The deportation was a searing, and in some cases, radicalizing experience. Among the former diaspora in Kyrgyzstan was the first rebel president of Chechnya in the post-Soviet period, Dzhokhar Dudayev, said Edil Baisalov, a former presidential chief of staff in Kyrgyzstan.
Adnan Z. Dzarbrailov, head of a Chechen diaspora group in Kyrgyzstan, said in a phone interview that the Tsarnaev family lived near a sugar factory in the small town of Tokmok, about 40 miles from the Bishkek, Kyrgyzstan's capital. The last member of the family left years ago, he said. He described them as "intelligentsia," and said Dzhokhar and Tamerlan's aunt was a lawyer.
Yet that history does little to explain how the brothers became wanted criminals in a horrific act of terrorism, their images captured on grainy surveillance tape and broadcast across the nation.
Gilberto Junior, who owns a Somerville auto body shop, just saw them as "regular kids," albeit wealthy ones with a taste for expensive cars. So it did not especially alarm him when Dzhokhar rushed in Tuesday, the day after the bombing, and said he needed his car immediately -- never mind that the repairs had not been done, and that the white Mercedes wagon had no bumper and no taillights.
The younger Tsarnaev brother seemed nervous, he said. He was biting his nails, and his knees were bending back and forth a bit. It occurred to Mr. Junior that he might be on drugs.
"At the time, I didn't think about anything," Mr. Junior said. "How could I judge him? I knew that he was nervous -- that's it."