An explosion killed 14 people on a subway in St. Petersburg, Russia, on Monday. More than 40 other people were injured. The blast, which occurred while President Vladimir Putin was in the city, blew a hole in the side of a car as it traveled between two stations in the heart of the city, Russia’s second largest. Investigators were treating the incident as a possible terrorist attack. A separate shrapnel-filled explosive device was found and disarmed at a subway station, suggesting the possibility of a coordinated attack. Authorities in the former Soviet republic of Kyrgyzstan said Tuesday that one suspect was a Kyrgyz-born Russian citizen.