On Monday April 3, 2017, a briefcase bomb exploded in St. Petersburg, Russia a bomb between the populated Sennaya Ploshad Station and  Technological Institute Station. This horrific bombing injured 45 people and killed 14 others. Seven were killed instantly as the bomb went off, and then later 7 others died  while hospitalized. Another bomb was found and defused at Ploshchad Vosstaniya metro station in a fire extinguisher box. This is the first public transportation bombing in Russia since the 2010 Moscow Metro bombing that killed 40 people and injured over 100 people.

Suspect Akbarzhon Jalinlov has been identified to be responsible for both of the attaacks in Moscow, with his fingerprints on the second bomb. However, he is one of the 14 people that died due to the first bomb. Several other suspects have been arrested with connections to Jalilov, and are formally living in central Asia.

Source: https://en.wikipedia.org/wiki/2017_Saint_Petersburg_Metro_bombing