"As part of this work, several citizens of Central Asian republics who contacted Jalilov were identified. Objects of importance to the investigation were found, seized and sent for investigation during searches in an apartment where these people lived," Petrenko said.
On Monday, an explosion occurred in St. Petersburg in a subway train car on the stretch between the Sennaya Ploshchad and Tekhnologichesky Institut metro stations. Another blast that was supposed to take place on the Ploshchad Vosstaniya station was prevented by bomb technicians.
The explosion claimed the lives of at least 14 people, 55 others remain in hospitals, some are in critical condition.
The Russian Investigative Committee has opened a criminal investigation into the suspected terrorist attack in the St. Petersburg metro but it is also following other leads.