On the calendar
April 15, 2013 was a Monday, the 105th day of 2013 with 260 days left in the year. It fell in ISO week 16.
Two bombs exploded near the Boston Marathon finish line on Monday, April 15, 2013. The blasts killed spectators Krystle Campbell, Lingzi Lu and eight-year-old Martin Richard. Hundreds of other people were hurt, many with severe leg injuries. What happened at the 2013 Boston Marathon became a story not only of an attack, but also of fast emergency care, an unusually public investigation and a city learning how to remember without giving the attackers the final word.
The marathon took place on Patriots’ Day, a Massachusetts holiday when downtown Boston is full of runners and spectators. The first explosion occurred on the north side of Boylston Street near the finish line. A second device exploded seconds later farther west. Medical tents, police officers, volunteers and trained spectators were already nearby, so tourniquets and trauma care began almost immediately.
The finish-line response
The area changed from a celebration to an emergency scene within seconds. Race volunteers and bystanders moved barriers, carried injured people and directed ambulances through crowded streets. Hospitals had prepared for routine marathon cases and were able to activate mass-casualty procedures. The concentration of medical resources close to the finish line saved lives.
Police closed a wide section of the Back Bay while bomb technicians checked abandoned items. Officials halted the race, leaving thousands of runners short of the finish. Family members struggled to locate one another as mobile networks became congested. Boston established a family assistance center, and hospitals began the difficult work of identifying patients and contacting relatives.
The devices were pressure cookers packed with explosive material and metal pieces, then placed in backpacks. Investigators treated Boylston Street as a large evidence field. They photographed the pavement, building fronts and debris before carefully collecting fragments that might show how the bombs were made or carried.
How the investigation narrowed
The FBI led the investigation with Boston police, Massachusetts State Police and other agencies. A central challenge was the amount of potential evidence. Businesses had security cameras, television crews had recorded the finish, and spectators supplied thousands of images and videos. Analysts synchronized those records by time and location rather than relying on a single dramatic image.
On April 18, the FBI released photographs and video of two men it described as Suspect One and Suspect Two. Officials asked the public to use only those official images. That caution mattered because online communities and some news organizations had already circulated incorrect identifications, causing distress to innocent families.
Later that night, Massachusetts Institute of Technology police officer Sean Collier was shot and killed in Cambridge. The suspects then carjacked a vehicle, and the driver escaped. A confrontation in Watertown followed early on April 19. One suspect died after the exchange; a transit police officer was seriously wounded.
The Watertown search and capture
Authorities asked people in Boston and several nearby communities to remain indoors while officers searched for the surviving suspect. Transit service stopped, streets emptied and armored vehicles moved through residential neighborhoods. The request was lifted late in the day after officials determined the organized search had not found him.
Soon afterward, a Watertown resident noticed something unusual in a covered boat behind his house and contacted police. Officers surrounded the property and captured the wounded suspect that evening. The four-day sequence had stretched across the 2013 calendar from a Monday afternoon race to a Friday-night arrest.
The shelter request and massive police deployment later prompted careful review. Public-safety agencies studied how to coordinate radio systems, share information and communicate risk without spreading rumors. Emergency planners also examined the value of trained civilians and readily available bleeding-control equipment.
Trial, sentencing and legal review
Federal prosecutors charged Dzhokhar Tsarnaev with crimes including use of a weapon of mass destruction resulting in death. A jury convicted him in 2015 and imposed a death sentence. The federal appeals process continued for years: an appellate court initially vacated the death sentences, and the US Supreme Court restored them in 2022 after reviewing jury-selection and evidence questions.
The legal case could not resolve the physical and emotional injuries. Survivors faced repeated surgeries, rehabilitation, hearing loss and trauma. Some learned to use prosthetic limbs and returned to the marathon. Charitable donations through The One Fund Boston supported injured people and victims’ families, while separate programs assisted affected businesses and first responders.
What changed after April 15
Large races expanded screening, surveillance and coordination among medical and law-enforcement teams. Boston adjusted finish-area access and prohibited certain bags for participants and spectators. Across the country, emergency agencies increased training in hemorrhage control, including public education on tourniquet use.
The attack also demonstrated the risks of an investigation conducted in real time before a national audience. Official requests for photographs produced useful evidence, yet internet speculation also accused people who had no connection to the crime. That contrast remains a practical lesson: crowdsourced information can assist investigators, but unverified identification can do lasting harm.
Boston’s public memory centers on the people affected and those who helped. One Boston Day encourages service each April 15. The marathon returned in 2014 with an unusually large field and strong security. Visitors researching other dates from that year can use the full 2013 US calendar, while the site’s day-of-week calculator confirms that April 15, 2013 was a Monday. Those calendar facts locate the event; the names, recovery and community response explain why the date still carries weight.
Frequently asked questions
What happened at the Boston Marathon in 2013?
Two homemade bombs exploded near the Boylston Street finish line on April 15, 2013. Three spectators were killed and hundreds of people were injured. Investigators rapidly collected video, photographs and physical evidence, then identified two brothers as suspects. One died after a confrontation with police; the other was captured on April 19.
Where were the Boston Marathon bombs placed?
Both devices were left near the finish line on Boylston Street in Boston. They were separated by roughly a block and exploded seconds apart. The location was crowded with spectators, volunteers, runners and medical personnel, which helped rescuers respond quickly but also meant many people were exposed to the blasts.
How did investigators identify the suspects?
Investigators combined surveillance video, photographs submitted by the public, witness information and evidence recovered from the scene. The FBI released images of two suspects on April 18. Events then moved quickly through Cambridge and Watertown, ending when the surviving suspect was found hiding in a covered boat.
How is the 2013 attack remembered in Boston?
Boston marks April 15 as One Boston Day, encouraging service and acts of kindness. Memorials and annual marathon ceremonies honor those killed, survivors, first responders and bystanders who helped. The permanent Boylston Street memorial identifies the places near which the two bombs exploded without turning the site into a spectacle.
Sources
- Boston Marathon bombing case history - FBI
- Boston Marathon bombing prosecution - Department of Justice
- One Boston Day - City of Boston
Facts in this article were checked against the sources above. See our editorial policy to report a correction.