Investigation

No individuals or terrorist organization claimed responsibility for the attack.^[12] Although initial reports speculated the explosion had been caused by an "unidentified explosive device", possibly a gas leak, eyewitness testimony and physical evidence recovered from the site of the explosion enabled investigators to quickly determine the blast had been caused by a female suicide bomber wearing a green hijab who, according to one survivor, had been "looking out the window, acting calm [and] not drawing any attention to herself" immediately before detonating her device.^[13] An identity card recovered within the bus confirmed the identity of the suicide bomber as 30-year-old Naida Asiyalova^[14] and within hours of the explosion, a spokesman for the Investigative Committee of Russia named her husband, Dmitry Sokolov, as a prime suspect in the attack.^[15]

The explosive device consisted of two blocks of TNT weighing between 500 and 600 grams and two grenades (one of which failed to detonate in the explosion). In addition, Asiyalova had numerous shards of metal, screws, and bolts on her possession to maximize the devastation of the blast. Although one grenade had exploded when Asiyalova detonated her suicide belt, one unexploded grenade was discovered beneath the bus.^[8]

An investigation into Asiyalova's movements on the date of her death determined she had purchased a ticket to travel to Moscow via bus from Dagestan on the morning of 21 October, but had alighted the vehicle in Volgograd.^[16] Via an examination of CCTV footage, investigators determined Asiyalova had briefly entered a Volgograd shopping centre at 1:16 on the afternoon of her death, but had left the premises shortly thereafter before boarding the bus.^[17] As Asiyalova was found to have a ticket to travel to the capital on her possession at the time of the explosion, investigators believe the suicide attack was originally intended to take place at an unknown location in Moscow, although for unknown reasons, Asiyalova chose to detonate her device upon the bus.^{[16][lower-alpha 1]}

On the evening of the bombing, authorities within the Volgograd Oblast declared three days of mourning, commencing 22 October.^[19] The same day, the People's Republic of China condemned the bombing.^[20]

Asiyalova

Asiyalova was born in the Gunibsky District of Dagestan in the North Caucasus on 25 October 1982. She was raised in the capital city of Makhachkala, and relocated to Moscow to work as a store clerk at age 23. Shortly after relocating to Moscow, Asiyalova married a Turkish man, although the couple divorced by mutual consent shortly thereafter.^[21]

She first encountered her future husband and co-conspirator in the Volgograd bus bombing, Dmitry Sokolov, on a Russian dating website in 2010 when she was a 27-year-old divorcée and he an 18-year-old recent convert to Islam.^[21] According to Asiyalova's mother, Ravzat, her daughter began developing a keen interest in Islamic extremism the year she encountered Sokolov and was already markedly radicalized—having adopted the name Amaturahman.^{[lower-alpha 2]} Shortly after becoming acquainted online, the two agreed to meet and began dating shortly thereafter.^[22]

At the time of Asiyalova's death, she is known to have suffered from a fatal bone disease which had begun causing her jawbone to recede.^[7] Resultingly, Asiyalova became increasingly dependent on both painkillers and tranquilizers. These factors may have influenced her decision to become a suicide bomber.^{[23][lower-alpha 3]}

Sokolov

Sokolov (b. 10 July 1992) was an ethnic Russian born into a family of Orthodox Christians. His family originally hailed from Krasnoyarsk, Siberia,^[25] although his family relocated to Moscow when he was in his teens. He is believed to have converted to Islam while studying in the capital and shortly before he met his future wife in 2010. Following his conversion to Islam, Sokolov adopted the name Abdul Jabbar and began studying Arabic.

Prior to Sokolov's marriage to Asiyalova, he is not known to have displayed any traits of extremism. However, in the months following their marriage, he converted to a more radical version of the faith.^[26] He was reported missing by his family in July 2012 after he failed to return home from the Arabic language courses he attended at a Moscow mosque.^[18] Although his mother, Olga, had subsequently appealed for information as to the whereabouts of her son and daughter-in-law on the Russian TV series Wait For Me, she received no response.^[27]

It is believed that following their marriage, Asiyalova persuaded Sokolov to convert to a more radical form of Islam—Wahhabism. She is also known to have persuaded him to join Islamic militants in her native Dagestan, where he became a prominent explosives expert. In the months prior to the Volgograd bus bombing, Sokolov had been linked to two separate, non-fatal explosions which had injured 29 people.^[28] Consequently, by October 2013, both he and his wife were on a list of Russia's most wanted fugitives.^[29]