* Boston bombing suspects proud of Chechen heritage
* No evidence of motive so far for attacks
* Chechnya's independence bid crushed by Russian forces after two wars
* Chechen fighters have history of attacks on civilians
By Thomas Grove and Peter Graff
April 19 During the lifetime of the two Boston bombing suspects, their homeland Chechnya has seen two Russian invasions unleash some of Europe's worst bloodshed in generations, and produced fighters who have carried out horrific attacks on civilians.
So far there has been no claim of responsibility for the attacks on the Boston Marathon or evidence made public of the motivations of the suspects, brothers Tamerlan and Dzhokhar Tsarnaev.
Both have left a trail on the Internet suggesting they were devout Muslims, proud of their Chechen heritage and supportive of the region's bid for independence from Moscow.
Although it is not clear whether they ever lived in Chechnya, they were both enrolled in a school in Dagestan, a neighbouring region that was drawn into Chechnya's violence during the 1990s and has since become the focal point for a simmering Islamist insurgency.
Both provinces are part of the North Caucasus, a mountainous strip of southern Russia populated mainly by Muslim ethnic minorities, with a history of rebellion against Moscow - and brutal Russian repression - dating back centuries.
In Tsarist times, Russian forces fought constant wars against fighters from the Chechen, Dagestani, Ingush and other ethnic groups. Under Stalin, the entire Chechen people was deported to distant central Asia as a potentially hostile nation. Although some returned, some stayed, and there have been reports that the Tsarnaevs were raised in remote Kyrgyzstan.
When the Soviet Union broke up in 1991, Chechens sought independence like the people of the 14 other ex-Soviet republics that left Moscow's orbit. But Moscow decided to fight rather than let them leave.
Bombing suspect Dzhokhar Tsarnaev was born in 1993 at a time when Chechnya was pursuing its independence, and his given name Dzhokhar is that of Dzhokhar Dudayev, the Chechen secessionist leader of the time. Dudayev was killed by a Russian missile in 1996 as his rebel forces were inflicting a humiliating defeat on Russian troops.
Moscow withdrew its forces after a two-year fight but Vladimir Putin, then prime minister, sent them back in 1999, this time crushing the independence movement and putting in place a hand-picked loyalist leader whose son now runs the region with an iron fist.
The two Chechen wars killed tens of thousands of civilians, mainly as a result of mass Russian bombardment of the capital Grozny and villages in the mountains. Hundreds of thousands of people were driven from their homes.
During and after the conflicts, Chechen fighters increasingly adopted Islamist rhetoric and the tactics of ever-deadlier and more brazen attacks in Russia, frequently targetting civilians in mass bombings and hostage takings.
In 2002 Chechen fighters seized a Moscow theatre. When Russian troops stormed it, 129 hostages and 41 Chechen guerrillas were killed.
The attacks culminated in the siege of a primary school in the town of Beslan outside Chechnya in 2004. They rigged the school with explosives and held children hostage. When Russian troops stormed the building, 331 hostages were killed, half of them children.
The attacks in Boston could bolster Putin, now president, who has long argued that Chechen separatists are nothing but terrorists and asked for the West's support.
Today, the North Causasus region still faces violence from an insurgency led by an Islamist group, the Caucasus Emirate, led by a former Chechen independence guerrilla commander, Doku Umarov. Much of the violence is focused on Dagestan.
The Caucasus Emirate claimed responsibility for a suicide bombing at Moscow's Domodedovo airport in January 2011 that killed 37 people and for suicide bombings on the Moscow subway that killed 40 people in 2010.
Security is an important issue for the 2014 Winter Olympics, which will be held in Sochi, a peaceful part of the North Caucasus hundreds of miles from Chechnya.
On his social media web page, Boston bombing suspect Dzhokhar Tsarnaev jokes about the reputation of people from the North Caucausus for conflict with the authorities: "A car goes by with a Chechen, a Dagestani and an Ingush inside. Question: who is driving?"
The answer: the police. (Reporting by Thomas Grove, Editing by Timothy Heritage)