A day after Monday's attack, security officials raided the apartment of Akbarzhon Jalilov - the main suspect in the suicide bombing on the St Petersburg metro that killed 14 people.
Tracking Akbarzhon Jalilov:
- Jalilov was born in 1995 in Kyrgyzstan, a mainly Muslim ex-Soviet republic in central Asia, and held a Russian passport.
- Jalilov moved into the rented apartment, in a Soviet-built nine-storey building in north-eastern St Petersburg, coincided with his return from a visit to his home city of Osh in southern Kyrgyzstan.
- Two Kyrgyz government sources told Reuters that Jalilov made the trip in February, leaving in early March on a flight to Moscow.
- Osh is part of the Fergana Valley, a fertile strip of land that straddles Kyrgyzstan, Uzbekistan and Tajikistan and is mainly populated by ethnic Uzbeks. It has a tradition of Islamist radicalism and hundreds of people have set out from the area to join Islamic State in Syria and Iraq.
- Jalilov had previously lived in St Petersburg for several years. It was not clear where he had been living before his trip back to Osh, or why he moved to a new apartment.
- The apartment Jalilov rented in St Petersburg is about 20 km from the site of the explosion, in the centre of the city.
- Neighbours at the building said that Jalilov had first moved into apartment 109 around a month ago. They said the young man they had seen around the building matched pictures of Jalilov released to Russian media since the bombing.
- "The apartment was always silent," said a resident of the same staircase, who gave her name as Margarita. "When the owner let (the apartment) I asked her and she said he was a decent guy and that I should call her if he makes noise." "But I never heard ... any music playing. Maybe he turned on the TV once." She said on one occasion about five people who appeared ethnically Russian had visited him, but there seemed nothing remarkable about that. A second resident also said Jalilov had been a tenant in the building.
- Jalilov's parents, who say they had not seen their son for a while, were due to fly into St Petersburg on Wednesday and a Reuters witness at Pulkovo airport reported heavy security.
- In the several years Jalilov spent living in Russia, he blended into the millions of migrants from central Asia, and led an outwardly secular lifestyle. His profile on VKontakte, the Russian equivalent of Facebook, showed he was interested in pop music, fast cars, and boxer Mike Tyson.
- His aunt, Surayo Jalilova, told Reuters in Osh: "We are speechless, we were all shocked, we never thought he could do something like this. He was the most obedient kid in the family, did well at school."
- Fatima Kadyrakhunova, who was his class teacher for four years at School no. 26 in Osh, said he was quiet and reserved, but did not excel at his studies.