With the dragnet over in the Boston Marathon bombing, attention has turned to the history of the Tsarnaev family, especially over the last few years. When they first arrived in the US, the Tsarnaevs were refugees looking for a better life, far from the conflicts of their Chechnyan homeland — a pattern of flight that was almost 70 years old in the Tsarnaev family. What changed? According to the Wall Street Journal, Tamerlan became immersed in a more radical form of Islam, joined by his mother — which split the family.

Law-enforcement officials trying to understand what happened in Boston are looking into whether Tamerlan Tsarnaev had taken a turn toward radical Islam. Among the things they are examining: a six-month trip he took last year to Dagestan, a republic in Russia’s south, bordering Chechnya. A close examination of the Tsarnaev family shows that, over the past five years or so, the personal lives of the family members slipped into turmoil, according to interviews with the parents, relatives and friends. The upheaval in the household was driven, at least in part, by a growing interest in religion by both Tamerlan and his mother. Once known as a quiet teenager who aspired to be a boxer, Tamerlan Tsarnaev delved deeply into religion in recent years at the urging of his mother, who feared he was slipping into a life of marijuana, girls and alcohol. Tamerlan quit drinking and smoking, gave up boxing because he thought it was in opposition to his religion, and began pushing the rest of his family to pursue stricter ways, his mother recalled. … The changes drove a wedge through the Tsarnaev home at 410 Norfolk St., in Cambridge, Mass. Tamerlan persuaded his mother to cover herself up, which she says at one point distressed her husband, Anzor. “He said, ‘You are being crazy, covering yourselves,'” she recalled her husband saying. She said that she told him, “This is what Islamic men should want. This is what I am supposed to do.” The parents’ marriage broke up about two years ago. The father—a former boxer himself who was distraught when Tamerlan gave up the sport—has since moved to Dagestan after falling ill. Both parents believe that their sons are being framed for the Boston attack.

This closeness led Tamerlan to make one final phone call to his mother during the police chase that ended his life on Friday morning:

Days later, it was the son who phoned his mother. The two, in recent years, had shared a powerful transformation to a more intense brand of Islam. “The police, they have started shooting at us, they are chasing us,” Mrs. Tsarnaeva says Tamerlan told her. “Mama, I love you.” Then the phone went silent.

Until now, I hadn’t seen that fact reported, although I certainly might have missed it in the deluge of information over the last few days. The WSJ apparently gleaned it from the mother during their interview. The entire article is worth reading at least for background material on the evolution in the Tsarnaev family, with some familiar information included with a few new tidbits about the warning signs of Tamerlan’s increasing radicalism.

ABC News also has a video up of Tsarnaev family history, most of it treading over now-familiar ground, but with some interesting back story on the family’s attempt to avoid the conflict in Chechnya:

The timing of Tamerlan’s trip to Russia is intriguing, especially since his father wasn’t there until late in Tamerlan’s visit, according to ABC’s timeline:

A few years ago — the aunt did not recall exactly when — the father was severely beaten by what she described as a group of Russian athletes as he tried to defend another person from them. The beating left him with medical problems that did not improve with treatment in the United States. Eventually, with his health failing and having lost a significant amount of weight, the father decided to come back to Dagestan in May 2012. Tamerlan, his oldest son, had just arrived there a couple months earlier. Anzor Tsarnaev decided to pursue medical treatment, figuring that if he died, he would at least be buried here. The mother eventually joined him in Dagestan a month later.

Tamerlan didn’t just stick around Dagestan, either:

During his six-month stay in Dagestan, Tamerlan made several trips to Chechnya to visit relatives, his aunt said. He returned to the United States in September, departing the region from the airport in Grozny, the Chechen capital.

Apparently, that never set off any red flags in either Russia or the US. Neither did a two-year-old triple homicide that friends now believe isn’t a coincidence:

Former associates of slain Boston Marathon bombing suspect Tamarlan Tsarnaev now believe he may have been involved in a 2011 triple murder that claimed the life of his closest American friend, Brendan Mess. “At the time none of would have thought it was Tam. It was just so emotional and we thought we had someone else who had done it. Tam’s name wasn’t coming up at all,” said one of their mutual friends, who asked to be identified by his first name, Ray. Now “a few of my friends, without even speaking about it beforehand have all been thinking” that Tsarnaev could have been connected to the 2011 murder, he said. Ray and Tsarnaev were both part of a social circle centered on the gym at which Tsarnaev trained and on a Boston hip-hop group called FlyRidaz, whose members this week expressed shock at having known the suspected killer.

In part, that comes from recollections of Tsarnaev’s odd behavior at the time of his close friend’s murder:

The owner of the Wai Kru Mixed Martial Arts in Allston, John Allan, told reportersthat Tsarnaev described Mess to him as his “best friend.” So the Cambridge crew were surprised in the fall of 2011 that Tsarnaev didn’t show up at his best friend’s funeral. Now, they see it as a clue. “Tam wasn’t there at the memorial service, he wasn’t at the funeral, he wasn’t around at all,” Ray said. “And he was really close with Brendan. That’s why it’s so weird when he said ‘I don’t have any American friends.'” “He was somebody who was in contact with Brendan on a daily basis. Anybody like that you would think they would have been around,” Ray said.

The police have always suspected that the murderers were known to the victims, due to the lack of forced entry, but apparently never had Tsarnaev on their radar screens. That may change after the last week — or it may just be a coincidence. After reading the history of Tamerlan’s radicalization, though, the 2011 time frame seems to be when his fervor was beginning to peak. That might pique the curiosity of investigators stymied by this unsolved murder, too. In fact, it already has:

Authorities are investigating whether the Boston Marathon bombing suspect who died after a shootout with police had any connection to an unsolved triple homicide in suburban Boston in 2011, a spokeswoman for prosecutors said on Monday. The 26-year-old Tamerlan Tsarnaev, identified by the FBI as one of two brothers suspected in last Monday’s blasts, was a close friend of one of three men who were stabbed in the neck in an apartment in Waltham, Massachusetts in September, 2011. At the time, the Middlesex County District Attorney’s office said it appeared that the victims knew their assailant or assailants and that the attacks were not random. Tsarnaev’s potential connection to the case surfaced after the website Buzzfeed.com reported that some of his former associates suspect he may have been involved in the murder. “We are definitely going to pursue any new leads,” said Stephanie Guyotte, a spokeswoman for the Middlesex District Attorney’s office. She said it was fair to say that investigators will check to see if Tsarnaev had anything to do with the crime.

I wonder what else they may find ….