The Boston Marathon bombings and subsequent shootings were a series of attacks which began on April 15, 2013. Three spectators were killed in the bombings: Krystle Marie Campbell, Lu Lingzi, and Martin William Richard. On April 18, 2013, MIT police officer Sean A. Collier was killed in an ambush. An estimated 264 others were injured. Suspect Dzhokhar Tsarnaev faces 30 charges, including using a weapon of mass destruction.