On 27 November 2009 at 21:34 local time, a bomb exploded beneath the Nevsky Express, a high-speed train travelling from Moscow to Saint Petersburg, causing it to derail near the town of Bologoye in Tver Oblast, roughly 200 miles from Moscow. The train was reported to be carrying 661 passengers across 13 carriages, with the last four cars affected by the derailment. Russian officials initially stated that 39 people had been killed and 95 injured, but this figure was later retracted; by 2 December, 27 deaths had been reported. Residents of the nearby village of Lykoshino were the first to respond, and a field hospital was set up while at least 50 injured people were hospitalised in Saint Petersburg.
Initial reports attributed the derailment to an electrical fault, but investigators later found a crater near the track, leading to suspicion of a terrorist attack. Alexander Bortnikov, head of the FSB, reported to President Dmitry Medvedev that the train had been derailed by an explosion. The Russian government subsequently confirmed the incident was caused by terrorists, making it, according to reporting, Russia's deadliest attack outside the North Caucasus region since the 2004 Russian aircraft bombings. A second, weaker bomb exploded the following day, 28 November, near the site of the first blast, apparently targeting investigators; it injured Alexander Bastrykin, head of the Investigative Committee, the highest-ranking official to visit the scene, though no deaths resulted.
Among those killed were Boris Evstratikov, head of Rosreserve; Sergei Tarasov, chairman of Rosavtodor and a former representative of St. Petersburg in the Federation Council of Russia; and Lyudmila Mukhina, deputy head of the Office of Science of Rosrybolovstvo. Officials injured included Dmitry Goin and Alexander Poshivay, both of Rosreserve.
President Medvedev ordered an FSB investigation, and a criminal case was opened under Russian Criminal Code articles covering terrorism and illegal possession of weapons or explosives. Responsibility for the attack was initially claimed by far-right nationalists, and later by a group described as the "Caucasian Mujahadeen" acting on orders from Dokka Umarov, described as leader of the Islamist insurgency in the North Caucasus. Investigators noted similarities to the 2007 Nevsky Express bombing. Evidence linked to the case was reportedly found following a March 2010 raid in which Said Buryatsky, described as a close associate of Umarov, and seven other suspects were killed.
On 31 March 2010, charges of terrorism, participation in unlawful armed formations, and illegal trafficking in explosives and ammunition were filed against 12 ethnic Ingush men from the village of Ekazhevo, 11 of whom bear the surname Kartoyev and are related, and a twelfth, Zelimkhan Aushev. A final indictment was filed on 20 January 2011, naming nine Kartoyevs and Aushev.