Boston Marathon bombing

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. Brothers Tamerlan and Dzhokhar Tsarnaev planted two homemade pressure cooker bombs that detonated near the finish line of the race 14 seconds and 210 yards (190 m) apart. Three people were killed and hundreds injured, including a dozen victims that lost limbs.

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. Later on the evening of April 18, the Tsarnaev brothers killed an MIT policeman, Sean Collier, and proceeded to commit a carjacking. 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). Tamerlan was shot several times, and his brother Dzhokhar ran him over while escaping in the stolen car. Tamerlan died soon thereafter.

An unprecedented search for Dzhokhar Tsarnaev ensued, with thousands of law enforcement officers in Tactical Armed Vehicles searching door-to-door 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. Dzhokhar was soon discovered hiding in a boat in the backyard of a Watertown resident. He was shot and wounded by police before being taken into custody on the evening of April 19.

During questioning, Dzhokhar 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 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. He was convicted of 30 charges, including use of a weapon of mass destruction and malicious destruction of property resulting in death.

Two months after his conviction, he was sentenced to death, but the sentence was vacated by the United States Court of Appeals for the First Circuit. A writ of certiorari was granted by the Supreme Court of the United States, which considered the questions of whether the lower court erred in vacating the death sentence. After hearing arguments as United States v. Tsarnaev, the Court upheld the death penalty, reversing the First Circuit Court's decision on March 4, 2022.

Bombing

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.

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.

Initial investigation

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

Release of suspect photos

Jeff Bauman was immediately adjacent to one of the bombs and lost both legs; he wrote while in the hospital: "Bag, saw the guy, looked right at me". He later gave a detailed description of the suspects, which enabled images of them to be identified and circulated quickly.

At 5:00 p.m. on April 18, three days after the bombing, the FBI released images of two suspects carrying backpacks, asking the public's help in identifying them. The FBI said that they were doing this in part to limit harm to people wrongly identified by news reports and on social media. As seen on video, the suspects stayed to observe the chaos after the explosions, then walked away casually. The public sent authorities a deluge of photographs and videos. The FBI-released images depicted Dzhokhar and Tamerlan Tsarnaev.

MIT shooting and carjacking

Hours after the FBI released photos of the two suspects in the bombing, Tamerlan and Dzhokhar Tsarnaev visited their family's apartment in Cambridge. There, they obtained five improvised explosive devices (IEDs), ammunition, a semiautomatic handgun, and a machete. The two brothers then drove to the Massachusetts Institute of Technology.

On April 18, 2013 at 10:25 p.m., the Tsarnaev brothers ambushed and shot Sean A. Collier of the Massachusetts Institute of Technology Police Department six times. The two brothers were attempting to steal Collier's Smith & Wesson M&P45 sidearm, which they could not free from his holster because of its security retention system. Collier, aged 27, was seated in his police car near Building 32 on the Massachusetts Institute of Technology campus. He died shortly after the shooting.

The brothers then carjacked a Mercedes-Benz M-Class SUV in the Allston-Brighton neighborhood of Boston. Tamerlan took the owner, Chinese national Dun "Danny" Meng (Chinese: 孟盾), hostage and told him that he was responsible for the Boston bombing and for shooting Collier. Dzhokhar followed them in their green Honda Civic, later joining them in the Mercedes-Benz. Interrogation later revealed that the brothers "decided spontaneously" that they wanted to go to New York and bomb Times Square.