During the annual Boston Marathon on April 15, 2013, two homemade pressure cooker bombs detonated 14 seconds and 210 yards (190 m) apart at 2:49 p.m., near the finish line of the race, killing 3 people and injuring several hundred others, including 16 who lost limbs.
Three days later, the Federal Bureau of Investigation (FBI) released images of two suspects, who were later identified as Chechen Kyrgyzstani-American brothers Dzhokhar Tsarnaev and Tamerlan Tsarnaev. They killed an MIT policeman, kidnapped a man in his car, and had a shootout with the police in nearby Watertown, during which two officers were severely injured, one of whom died a year later. Tamerlan was shot several times, and his brother Dzhokhar ran him over while escaping in the stolen car; Tamerlan died soon after.
An unprecedented manhunt for Dzhokhar ensued on April 19, with thousands of law enforcement officers searching a 20-block area of Watertown; residents of Watertown and surrounding communities were asked to stay indoors, and the transportation system and most businesses and public places closed. Around 6:00 p.m., a Watertown resident discovered Dzhokhar hiding in a boat in his backyard. He was shot and wounded by police before being taken into custody.
During questioning, Dzhokhar said that he and his brother were motivated by extremist Islamist beliefs and the wars in Iraq and Afghanistan, that they were self-radicalized and unconnected to any outside terrorist groups, and that he was following his brother's lead. He said they learned to build explosive devices from the online magazine of Al-Qaeda in the Arabian Peninsula. He also said they had intended to travel to New York City to bomb Times Square. On April 8, 2015, he was convicted of 30 charges, including use of a weapon of mass destruction and malicious destruction of property resulting in death. Two months later, he was sentenced to death.
The blasts (red) occurred along the marathon course (dark blue), the first nearer the finish line than the second.
The 117th annual Boston Marathon was run on Patriots' Day, April 15, 2013. At 2:49 p.m. EDT (18:49 UTC), two bombs detonated about 210 yards (190 m) apart at the finish line on Boylston Street near Copley Square. The first exploded outside Marathon Sports at 671–673 Boylston Street at 2:49:43 p.m. At the time of the first explosion, the race clock at the finish line showed 04:09:43 – the elapsed time since the Wave 3 start at 10:40 a.m. The second bomb exploded at 2:49:57 p.m., 14 seconds later and one block farther west at 755 Boylston Street. The explosions took place nearly three hours after the winning runner crossed the finish line, but with more than 5,700 runners yet to finish.
Windows on adjacent buildings were blown out but there was no structural damage. Runners continued to cross the line until 2:57 p.m.