Makeshift tribute to Boston Marathon Bombing victim Krystle Campbell at Copley on Boylston Street in the aftermath of the Boston bombing. At 2:50pm on Monday, April 15th two bombs were exploded on Boyston Street in Boston, one near the finish line for the Boston Marathon. Runners were approaching the finish line as the first bomb was detonated. Three spectators were confirmed dead, and over 170 injured. Main suspect Tamerlan Tsarnaev was killed after a shootout with police on the evening of Thursday, April 18th. His 19 year old brother Dzhokhar Tsarnaev was arrested on Friday evening after a massive search and lockdown of Boston, Cambridge and Watertown.