The Boston Marathon Bombing was a terrorist attack that occurred on April 15, 2013, when two bombs went off near the finish line of the Boston Marathon, killing three spectators and wounding more than 260 other people. After an intense manhunt, police captured one of the bombing suspects, 19-year-old Dzhokhar Tsarnaev, whose older brother and fellow suspect, 26-year-old Tamerlan Tsarnaev, died following a shootout with law enforcement. Investigators concluded that the Tsarnaevs, who spent part of their childhoods in the former Soviet republic of Kyrgyzstan, planned and carried out the attack on their own and were not connected to any terrorist groups.

Boston Marathon

April 15, 2013, marked the 117th running of the Boston Marathon, the world’s oldest annual marathon.

The popular event is held on Patriots’ Day, which commemorates the 1775 battles of Lexington and Concord that kicked off the Revolutionary War. Celebrated on the third Monday in April, Patriots’ Day is a legal holiday in Massachusetts.

The 2013 marathon began in the town of Hopkinton, west of Boston, with some 23,000 participants. The elite women runners started at 9:32 a.m., while the top male runners and a first wave of thousands of other runners followed at 10 a.m. Additional waves of runners took off at 10:20 a.m. and 10:40 a.m.

Rita Jeptoo of Kenya was the first female across the finish line, completing the 26.2-mile course, which traveled through eight Bay State towns and cities, in 2 hours, 26 minutes and 25 seconds. Lelisa Desisa of Ethiopia, the men’s winner, finished with a time of 2 hours, 10 minutes and 22 seconds.

Pressure-Cooker Bombs

At approximately 2:49 that afternoon, with more than 5,600 runners still in the race, two pressure-cooker bombs—packed with shrapnel and hidden in backpacks among crowds of marathon-watchers—exploded within seconds of each other near the finish line along Boylston Street.

The blasts instantly turned the sun-filled afternoon into a gruesome scene of bloodshed, destruction and chaos.

Three spectators died: a 23-year-old woman, a 29-year-old woman and an 8-year-old boy, while more than 260 other people were wounded. Sixteen people lost legs; the youngest amputee was a 7-year-old girl.

Tsarnaev Brothers

An investigation involving more than 1,000 federal, state and local law enforcement personnel was immediately launched.

A breakthrough in the case came less than two days later, when FBI analysts, poring through thousands of videos and photographs taken from security cameras in the area where the attack occurred, pinpointed two male suspects. The FBI released surveillance-camera images of the men, whose identities were then unknown, on the evening of April 18.

That night at around 10:30, Sean Collier, a 27-year-old police officer at the Massachusetts Institute of Technology, was shot dead in his patrol car on the school’s Cambridge campus. Authorities later would link the murder to the Tsarnaev brothers, who allegedly attempted to steal the officer’s service weapon.

Soon after Collier was killed, Tamerlan Tsarnaev carjacked a Mercedes SUV at gunpoint, taking the driver hostage and telling him he was one of the Boston Marathon bombers. Dzhokhar Tsarnaev followed behind in a Honda Civic before joining his older brother and the hostage in the SUV.

The brothers drove around the Boston area with their hostage, forcing him to withdraw money from an ATM and discussing driving to New York City.

Tamerlan Tsarnaev

When they stopped at a Cambridge gas station, the hostage escaped and called police, informing them the SUV could be tracked by his cellphone, which was still in the vehicle.

Shortly after midnight, police in the Boston suburb of Watertown spotted the suspects in the stolen SUV and Honda Civic and tried to apprehend them. A gun battle broke out on a Watertown street, with the Tsarnaevs exchanging fire with the police and hurling explosive devices at them. One officer was seriously injured by gunshots but survived.

After Tamerlan Tsarnaev was tackled by police, his brother Dzhokhar drove the stolen SUV straight at them, running over his brother before speeding away. He abandoned the SUV nearby then fled on foot.

A gravely wounded Tamerlan Tsarnaev, whose body was riddled with bullets, was taken to a hospital, where doctors were unable to resuscitate him.

Dzhokhar Tsarnaev

That day, April 19, the Boston area was put on lockdown, with schools closed, public transportation service suspended and people advised to stay inside their homes, as police conducted door-to-door searches in Watertown and military-style vehicles patrolled the streets.

That evening, after law enforcement called off their search of the area, a Watertown man went out to his backyard to check on his dry-docked boat. When he looked inside the covered, 24-foot vessel, he was startled to see blood and a person, later identified as Dzhokhar Tsarnaev, hiding there.

The Watertown man immediately called 911, police arrived and surrounded the boat, and the alleged terrorist, who was wounded from the earlier gun battle, was taken into custody. Before his capture, Tsarnaev reportedly scrawled a note inside the boat indicating the Boston bombings were committed in retaliation for U.S. wars in Muslim countries.

Bombing Suspects

At the time of the bombings, Dzhokhar Tsarnaev was a sophomore at the University of Massachusetts Dartmouth and Tamerlan Tsarnaev, a former amateur boxer, was married and had a young child.

The brothers were Muslims, born in the former Soviet Union republic of Kyrgyzstan in 1986 and 1993. Dzhokhar Tsarnaev arrived in the United States with his parents in 2002, and the family soon applied for political asylum and settled in Cambridge. Tamerlan and his two sisters followed the family to America in 2003.

The siblings’ father, an ethnic Chechen who grew up in Kyrgyzstan, found work as a car mechanic while their mother, an ethnic Avar from Dagestan, worked as a facialist.

Dzhokhar Tsarnaev, described by classmates as a popular student, became a naturalized U.S. citizen on September 11, 2012. His older brother, a community college dropout who was frequently unemployed, had a green card but was not an American citizen.

Investigators have suggested the Tsarnaevs were motivated by extremist Islamic beliefs but planned and carried out the bombings on their own and were not connected to any terrorist groups. The brothers allegedly used the Internet to learn how to build explosives.

Boston Marathon Bombing Trial

In July 2013, Dzhokhar Tsarnaev pleaded not guilty to the 30 federal charges against him, including the use of a weapon of mass destruction resulting in death.

Tsarnaev was found guilty by a jury of all 30 charges against him on April 8, 2015 and was sentenced to death by lethal injection. At his trial, he apologized to survivors and family members of the victims. He was sent to the federal supermax prison in Florence Colorado, where he was incarcerated with terrorists such as Unabomber Ted Kaczynski and airline “shoe bomber” Richard Reid. Tsarnaev’s death sentence was later overturned by a federal appeals court, on grounds of possible jury exposure to media coverage and exclusion of evidence, but in March 2022 it was reinstated by the U.S. Supreme Court.

On April 15, 2014, the mayor of Boston and the governor of Massachusetts hosted a ceremony honoring the marathon bombing victims along with the first responders on the scene. The 118th running of the marathon took place the following week. The 5,633 runners who were prevented from completing the 2013 marathon due to the bombings were guaranteed a spot in the 2014 race.