2009 The Nevsky Express is bombed
Twenty-seven people died and another 130 people were hurt in a blast which hit the last three carriages of the high-speed Moscow-to-St Petersburg Nevsky Express. At first, the incident was blamed an an electrical fault but various terrorist groups began to claim credit for the outrage. Finally, blame was credibly settled on the forces of Dokka Umarov (aka Dokka Usman), the head of the so-called Caucasus Emirate, a pan-Islamic jihadist movement.
Since the sixteenth century, the Russian empire had been expanding eastward on to the vast steppes populated largely by Muslim peoples. In the 1700s they penetrated the Caucasus, meeting resistance from the fierce mountain tribes and the Persians who also controlled the area. It was not until the mid-nineteenth century that the Russian hold on these territories became relatively secure. That did not mean that opposition ceased. There were a number of risings by Chechens, Dagestanis and Ingushetians culminating in the proclamation of an independent Mountainous Republic of the Northern Caucasus in the dying days of the Romanov dynasty. Independence was crushed by the nascent Soviet Union which absorbed these peoples in backward federal republics. When the Soviet Union collapsed, separatist movements started up again, engaging in attacks (often vile and terroristic) on Russian forces and their collaborators. Some of the rebels wanted only independence, but a significant wing, led by Dokka Umarov, wanted a unified Islamic state and were prepared to spread violence into Russia proper to gain their ends.
In 2012 a Russian court convicted ten suspects from the North Caucasus republic of Ingushetia for the bombing; nine of them were from the same family of separatist activists. Umarov seems to have been poisoned, probably by opponents inside his movement.