19-year-old Dzhokhar Tsarnaev, who was apprehended late Friday, and 26-year-old Tamerlan Tsarnaev 10-20 minutes before the blast (Photo: AP)
Their grandparents were deported by Stalin's police in the mass expulsion of Chechens in World War II. Their parents went to the United States from Dagestan in search of a better life. And they became adherents of radical Islam.
The family history of the Boston Marathon bombing suspects has shown how the turbulence of the Caucasus region reverberates far beyond Russia's own borders.
Dzhokhar Tsarnaev, 19, and his brother Tamerlan, 26, had lived in the United States for over a decade but their origins shed light on the experiences that turned the young men into suspected murderers.
Much has been made of their ethnic origins in Russia's Caucasus region of Chechnya, but their father Anzor was in fact born in the former Soviet republic of Kyrgyzstan where Tamerlan and Dzhokhar spent much of their youth.
Their grandparents were deported to Kyrgyzstan under the mass expulsion of hundreds of thousands of Chechens from their homeland in the Caucasus in 1944 after the Soviet authorities accused the entire people of mass collaboration with the Nazis.
In a lightning operation, the entire Chechen people were herded on to trains and shifted thousands of kilometres away to Central Asia, mostly to Kazakhstan but some, like the parents of Anzor Tsarnaev, to Kyrgyzstan.
Tens of thousands died on the way in freezing conditions and the Chechens were only allowed to return to their homeland in the late 1950s after Stalin's death.
After the collapse of the Soviet Union, Anzor left Kyrgyzstan with his family and went back to the Caucasus, an official with Kyrgyzstan's state security service GKNB told AFP in Bishkek.
But with the first Chechen war between separatists and the Kremlin under way, the family left the Caucasus and returned to Kyrgyzstan in 1995, living in the town of Tokmok where Tamerlan started attending school number two in 1998, the Kyrgyz official said.
According to Kyrgyz sources, Dzhokhar was born in Kyrgyzstan and had Kyrgyz citizenship. Tamerlan however was born in Kalmykia in southern Russia and had Russian citizenship.
The youngest son may have been named after Dzhokhar Dudayev, the leader of Chechen separatist rebels, who was killed by a Russian air strike in 1996.
According to the Kyrgyz government, the family in 2001 went back to Dagestan, the home region of the brothers' mother Zubeidat.
US-based Chechen surgeon and prominent diaspora figure Khassan Baiev, who knew the family, told the New Times weekly from the United States that they moved as ethnic tensions were by then also flaring in Kyrgyzstan.
Dagestan, then as now, was one of the poorest regions of Russia beset by unemployment and also an Islamist insurgency that spread from Chechnya.
The family did not stay long and in 2002 moved to the United States where they filed for refugee status and settled.
"Dagestan today, is the acutest hotspot in Russia," Grigory Shvedov, chief editor of specialist Internet newspaper Caucasian Knot (www.caucasianknot.info) told AFP.
"This development of terrorism and dissent is due to the high level of religiousness, the high level of corruption and the low level of control on the part of the federal centre. All these factors flourished in post-Soviet times"
In recent years Tamerlan apparently posted militant videos on a YouTube page bearing his name, and travelled to Dagestan and Chechnya for six months in 2012.
In the years after the second post-Soviet Chechnya war, the insurgency against the Kremlin began to be increasingly rooted in Islamic radicalism rather than separatism.
Whether he was linked in anyway to Chechen Islamist insurgents -- who want to create an "emirate" ruled by Sharia law across the Northern Caucasus - remains unclear.
The Vilayat Dagestan rebel group -- an offshoot of the Caucasus Emirate organisation of wanted militant leader Doku Umarov -- denied having any link to the Boston bombings.
According to Shvedov, the attraction of militancy could have been motivated by "the parents' recollection of the Chechen war, the memory of relatives of the Stalin deportation" as well as current issues like Syria and the Iraq war.
But the most powerful element is usually propaganda, based on idea of US domination and perceived attempts to destroy Islam, he said.