The Boston Marathon bombing, sometimes referred to as simply the Boston bombing, was an Islamist domestic terrorist attack that took place during the 117th annual Boston Marathon on April 15, 2013. Four hours into the race, Tamerlan Tsarnaev and Dzhokhar Tsarnaev detonated two homemade pressure cooker bombs containing explosives and steel shrapnel. The bombs were hidden inside two backpacks dropped in the cheering crowds just minutes prior, and remotely detonated near the finish line of the race in central Boston, 14 seconds and 210 yards (190 m) apart. Three people were killed and hundreds were injured, including 12 victims who suffered traumatic limb amputations.
On April 18, 2013, the Federal Bureau of Investigation (FBI) released images of two suspects in the bombing. The two suspects were later identified as the Tsarnaev brothers. Late on the evening of April 18, the brothers killed an MIT policeman, Sean Collier, in a failed attempt to steal Collier's service pistol, and proceeded to commit a carjacking close by. They engaged in a shootout with police in nearby Watertown, during which two officers were severely injured (one of the officers, Dennis Simmonds, died a year later from his injuries). Dzhokhar was struck in the face by a bullet, and Tamerlan was shot in the limbs and torso several times, followed by Dzhokhar striking him at high speed by the stolen car while attempting to run over police officers. Tamerlan was dragged down the road while stuck under the car, and died in a hospital soon after.
An unprecedented search for Dzhokhar Tsarnaev ensued, with thousands of law enforcement officers in tactical gear searching door-to-door in a roughly 20-block area of Watertown. Residents of Watertown and surrounding communities were asked to stay indoors. The public transportation systems, along with local businesses and public places, were closed or shut down. After a brief manhunt, a Watertown resident called 911 and alerted the police of the possible presence of Dzhokhar, who had climbed and hidden inside a boat under a white tarp, in his backyard. He was shot at and suffered multiple additional gunshot wounds during a several hours long standoff, which involved the use of armored vehicles, before surrendering. The police then took him into custody on the evening of April 19.
During questioning, Dzhokhar Tsarnaev acknowledged his role in the bombings. He said that he and his brother were motivated by the wars in Iraq and Afghanistan, that they were self-radicalized and unconnected to any outside terrorist groups, and that he was merely following his brother's lead. He said the brothers learned to build explosive devices from Inspire, the online magazine of al-Qaeda in the Arabian Peninsula. He also said that they had intended to travel to New York City to bomb Times Square. In April 2015, Dzhokhar Tsarnaev was convicted of all 30 charges in federal court, including the use of a weapon of mass destruction and malicious destruction of property resulting in death. Two months later, he was sentenced to the death penalty. The sentence was upheld on appeal by the Supreme Court of the United States on March 4, 2022. Dzhokhar has remained on death row ever since, and is currently incarcerated in the United States' maximum security prison, ADX Florence.
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 two 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.
Casualties and initial response
Rescue workers and medical personnel, on site as usual for the marathon, gave aid as additional police, fire, and medical units were dispatched, including from surrounding cities as well as private ambulances from all over the state. The explosions killed three civilians and injured 264 others.
Police, following emergency plans, diverted all remaining runners to Boston Common and Kenmore Square. The nearby Lenox Hotel and other buildings surrounding the scene were evacuated. Immediately after the bombing occurred and medically injured people were transported, the police closed a 15-block area around the blast site; this was reduced to a 12-block crime scene the next day. Boston police commissioner Edward F. Davis recommended that people stay off the streets.
Dropped bags and packages, abandoned as their owners fled from the blasts, increased uncertainty as to the possible presence of more bombs and many false reports were received. Simultaneously an electrical fire at the John F. Kennedy Presidential Library in nearby Dorchester was initially feared to be a bomb.
The airspace over Boston was restricted, and departures halted from Boston's Logan International Airport. Some local transit service was halted as well.
The Massachusetts Emergency Management Agency suggested that people trying to contact those in the vicinity use text messaging instead of voice calls because of the crowded cell phone lines. Cell phone service in Boston was congested but remained in operation, despite some media reports stating that cell service was shut down to prevent cell phones from being used as detonators.
The American Red Cross helped concerned friends and family receive information about runners and casualties. The Boston Police Department also set up a call helpline for people concerned about relatives or acquaintances to contact and a line for people to provide information. Google Person Finder activated their disaster service under Boston Marathon Explosions to log known information about missing people as a publicly viewable file.
Due to the closure of several hotels near the blast zone, a number of visitors were left with nowhere to stay; many Boston-area residents opened their homes to them.
The Federal Bureau of Investigation led the investigation, assisted by the Bureau of Alcohol, Tobacco, Firearms and Explosives, the Central Intelligence Agency, the National Counterterrorism Center, and the Drug Enforcement Administration. It was initially believed by some that North Korea was behind the attack.
United States government officials stated that no intelligence reports suggested such an attack. Representative Peter King, a member of the House Intelligence Committee, said: "I received two top secret briefings last week on the current threat levels in the United States, and there was no evidence of this at all."
Evidence found near the blast sites included bits of metal, nails, ball bearings, black nylon pieces from a backpack, remains of an electronic circuit board and wiring. A pressure cooker lid was found on a nearby rooftop. Both of the improvised explosive devices were pressure cooker bombs manufactured by the bombers. Authorities confirmed that the brothers used bomb-making instructions found in al-Qaeda in the Arabian Peninsula's Inspire magazine. After the suspects were identified, The Boston Globe reported that Tamerlan purchased fireworks from a fireworks store in New Hampshire.
April 18–19 shootings and search