Now that we know the names of the two men apparently responsible for the bombing at the Boston Marathon on Monday, Tamerlan Tsarnaev (26), who was killed early this morning in a shootout with police, and Dzhokhar Tsarnaev 19, who remains at large, we’re been unable to uncover a few facts and perhaps some clues on what may have sent these men down their road to destruction. From an estranged uncle, we learned this morning that the two brothers came to the United States in the early 2000s as refugees from the fighting in Chechenya and the general Caucasus region. That would mean that the younger brother would have been around 7 or 8, and the older brother in his early teens. They both attended local schools and went to college, although it appears that the older brother didn’t complete Community College and instead began pursuing a career in boxing with the hopes of making the U.S.Olympic Team. From there, things get interesting:

The suspect at large early Friday was Dzhokhar Tsarnaev, 19, born in Kyrgyzstan, who became a naturalized American citizen on Sept. 11, 2012, according to documents obtained by NBC News. He had a Massachusetts driver’s license and living in the Boston suburb of Cambridge. He was the suspect in the white hat in surveillance photos from the marathon released by the FBI.

His father, speaking from Russia, told The Associated Press that he was “a true angel” with an interest in medicine. He was registered as a student at the University of Massachusetts Dartmouth, the school said. He was awarded a $2,500 city scholarship toward college two years ago.

Sierra Schwartz, who identified herself as a high school friend of Dzhokhar Tsarnaev, told NBC News that he had lots of friends and did not seem to brood.

“He was a nice guy. He was shy,” she said. “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.”

Robin Young, who said her nephew was on the wrestling team with Dzhokhar Tsarnaev, told NBC News that he was “just a light, airy, curly-haired kid.”

(…)

The other brother, 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 studied at Bunker Hill Community College in Boston and wanted to become an engineer, according to a profile that appeared in a Boston University magazine in 2010. He said that he hoped to become an American citizen and one day join the U.S. Olympic boxing team.

He told the magazine that his family fled Chechnya in the 1990s because of the conflict there, and that he lived in Kazakhstan. While he had been in the United States for several years by that point, he said in the profile: “I don’t have a single American friend. I don’t understand them.”

He also said that he was a Muslim who did not smoke or drink.

Travel records obtained by NBC New York showed that Tamerlan Tsarnaev left the country for six months, from Jan. 12 to July 17, 2012, for Sheremetyevo, Russia. The records show that it was not until 6 a.m. Friday that he was labeled by American officials to be “a person or instrument that may pose a threat to the security of the United States.”

Sheremetyevo is an International Airport outside of Moscow but, obviously, that doesn’t explain where Tamerlan was for six months. The obvious question, of course, is whether he made is way to a Chechen rebel training camp of some kind where he was radicalized and trained before returning to the United States. It’s worth noting those that the father of these two men lives in Russia, apparently estranged from the mother who still lives in Massachusetts, so its possible that Tamerlan was simply spending an extended amount of time with him. So far, there seem to be more people who’ve come forward to speak about the younger brother, so he remains something of a mystery, even more so now that he’s dead.

Obviously, the first priority is to catch the outstanding suspect, but there seems to be some concern that these two men may have had confederates. In that case, we may be dealing with a whole new ballgame.

Of course, it does leave open the obvious question that James Joyner’s post left this morning. What, exactly, would two seemingly Americanized Chechen men, one of whom became a citizen just seven months before apparently planting a bomb in Copley Square, have against the United States to drive them to do this? Or, is this all just the product of one or more deranged minds?