(CBS News) Soon after the massive manhunt for the Boston Marathon bombing suspects ended, the search for answers and motives behind the attack took its place. Authorities are looking for any possible links to the .
"It's important to look at every aspect... their upbringing, where they came from, how they were raised, their nurture, their nature," Mary O'Toole, a former FBI criminal profiler told "CBS News This Morning: Saturday."
The Tsarnaev brothers named as suspects in the Boston attack are ethnic Chechens, although neither suspect was born there, a fact Chechen President Ramzan Kadyrov reiterated Friday in his dismissal of Chechen ties to the attack.
"They lived, studied, and grew up in America. They're to blame for such an upbringing, not us," Kadyrov said, "We don't bear any responsibility."
The Tsarnaev family fled the Republic of Chechnya -- a largely Muslim area in southern Russia -- in the 1990s, amid a bloody war between the army and Chechen separatist rebels.
The family initially fled to neighboring Kyrgyzstan, where Tamerlan was born in 1986, CBS News' Charlie D'Agata reports. Unhappy there, they moved again, to Dagestan where Dzhokhar, the 19-year-old suspect currently in custody, was born in 1993.
Several years later, the family immigrated to America. The father of the suspects spoke from Dagestan on Friday and insisted his sons were set up.
"We never even had weapons in the family. We escaped oppression and now look what's happened," Anzor Tsarnaev told reporters.
Chechen Islamists have long sought independence from Russia and have carried out some of the world's worst terrorist attacks in that pursuit. school raid in Beslan. 330 people were killed in the siege, half of them children., an incident that results in the killing of all 41 captors and 129 hostages by Russian Special Forces. In 2004, Chechen terrorists took hundreds of hostages in a
Juan Zarate, who served as Deputy National Security Adviser for President George W. Bush,that the Chechen separatist movement has been co-opted by anti-Western Jihadist groups including al Qaeda.
"The narrative of oppression has always been part of the global Jihahi narrative... and a reason to attack Russia and perhaps even the United States," Zarate said, adding that "the possibility here is that they were sensitized to the oppression and the issues in the region, may have radicalized over time, and perhaps had connectivity abroad."
"The history of Chechen terrorism is brutal and vicious...railway and subway attacks, suicide attacks on planes," Zarate added. "This is a region that has been roiled by terrorism for a long time."
Most interesting for American counter-terrorism officials, says Zarate, is that Chechnya has become "a source of operatives who have started to mix in the witch's brew of terrorism in places like western Pakistan."
told "CBS This Morning: Saturday" that the Chechen culture is characterized by "very fierce and proud people."
Knobel noted the history of violence between Chechens and Russians "that has been going on for hundreds of years," and which has seen "indiscriminate bombings of civilians."
"Undoubtedly, the parents told the kids about what being a Chechen is all about," Knobel said, "Their parents' Chechen culture would have had an effect on them even growing up in America."