Massachusetts Governor Charlie Baker and Boston Mayor Michelle Wu observe a moment of silence at the site of the Boston Marathon bombing memorial at...
Woman kneels and prays at the scene of the first explosion on Boylston Street near the finish line of the 117th Boston Marathon on April 15, 2013.
Police officers with their guns drawn hear the second explosion down the street. The first explosion knocked down 78-year-old US marathon runner Bill...
People tend to an injured woman on the corner of Exeter and Newbury Streets after two explosions went off near the finish line of the 117th Boston...
People gather near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15, 2013 in Boston, Massachusetts. Two people...
The memorial site in Copley Square to the Boston Marathon bombings is seen on Boylston Street April 30, 2013 in Boston, Massachusetts. Boston...
In this image released by the Federal Bureau of Investigation on April 18 two suspects in the Boston Marathon bombing walk near the marathon finish...
First responders tend to the wounded where two explosions occurred along the final stretch of the Boston Marathon on Boylston Street in Boston,...
Runner embraces another woman on the marathon route near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15, 2013...
Memorial set up at a barricade on Boylston Street, blocks away from the Boston Marathon explosions. Three days earlier, two explosions went off at...
In this image released by the Federal Bureau of Investigation on April 19 Dzhokhar Tsarnaev, 19-years-old, a suspect in the Boston Marathon bombing...
Police officers with their guns drawn hear the second explosion down the street. The first explosion knocked down 78-year-old US marathon runner Bill...
Volunteer sorts through unclaimed runners' bags after two explosions occurred along the final stretch of the Boston Marathon on Boylston Street in...
Person who was injured in the first explosion is wheeled across the finish line of the Boston Marathon.
Detailed view of flowers placed on a sidewalk on Boylston Street commemorating the two-year anniversary of the 2013 Boston Marathon bombings, on...
The injured are helped at the scene of the first explosion on Boylston Street near the finish line of the Boston Marathon.
April 22, 2013 Sports Illustrated via Getty Images Cover: Track & Field: Boston Marathon: Police officers draw their guns drawn after hearing the...
Police officers with their guns drawn hear the second explosion down the street. The first explosion knocked down 78-year-old US marathon runner Bill...
Member of the bomb squad investigates a suspicious item on the road near Kenmore Square after two bombs exploded during the 117th Boston Marathon on...
Second explosion goes off as 78-year-old US marathon runner Bill Iffrig was blown to the ground by the first explosion near the finish line of the...
Investigators in white jumpsuits work the crime scene on Boylston Street following yesterday's bomb attack at the Boston Marathon April 16, 2013 in...
Investigators in white jumpsuits work the crime scene on Boylston Street following yesterday's bomb attack at the Boston Marathon April 16, 2013 in...
Emergency personnel respond to the scene after two explosions went off near the finish line of the 117th Boston Marathon on April 15, 2013.
This cell phone image, taken in front of the Forum Restaurant, appears to show Boston Marathon bombing suspect, Dzhokhar A. Tsarnaev, near a young...
Items and crosses decorate a makeshift memorial April 20, 2013 on Boylston Street, near the scene of Boston Marathon explosions as people get back to...
David Ortiz of the Boston Red Sox poses with a Boston Strong sign, which honors the Marathon bombing victims, before a game the Kansas City Royals at...
Emergency personnel respond to the scene after two explosions went off near the finish line of the 117th Boston Marathon on April 15, 2013.
Runners and spectators flee from the scene where two explosions occurred along the final stretch of the Boston Marathon on Boylston Street in Boston,...
First responders rush to help injured people after two explosions occurred along the final stretch of the Boston Marathon on Boylston Street in...
First responders transport the wounded where two explosions occurred along the final stretch of the Boston Marathon on Boylston Street in Boston,...
Second explosion goes off as a runner was blown to the ground by the first explosion near the finish line of the 117th Boston Marathon.
Emergency personnel respond to the scene after two explosions went off near the finish line of the 117th Boston Marathon on April 15, 2013.
Officials react as the first explosion goes off on Boylston Street near the finish line of the 117th Boston Marathon on April 15, 2013.
Emergency personnel respond to the scene after two explosions went off near the finish line of the 117th Boston Marathon on April 15, 2013.
Two officials run away from the first explosion, right, on Boylston Street at the 177th Boston Marathon, April 15, 2013.
General view of the remembrance ceremony at the Boston Marathon Bombing Memorial at 755 Boylston Street, the location of the second attack of the...
Boston Marathon bombing survivors Heather Abbott and Noelle Lambert are introduced during a ceremony before a game between the Boston Red Sox and the...
Boston Marathon bombing survivors Celeste, Kevin, Sydney, and Tyler Corcoran are introduced during a ceremony before a game between the Boston Red...
Boston Marathon bombing survivors the Rent family are introduced during a ceremony before a game between the Boston Red Sox and the Baltimore Orioles...
Boston Marathon bombing hero Carlos Arredondo watches the New England Patriots Super Bowl victory parade on February 7, 2017 in Boston,...
Boston Marathon bombing survivor Patrick Downes celebrates with the Martin Richard family after finishing the 120th Boston Marathon on April 18, 2016...
Boston Marathon bombing survivors Patrick Downes and Jessica Kensky celebrate at the finish line with their dog Rescue and fellow runners after...
Boston Marathon bombing survivors Patrick Downes and Jessica Kensky celebrate at the finish line with their dog Rescue after Downes completed the...
Former Boston mayor Thomas Menino, mayor Marty Walsh, U.S. Vice President Joe Biden, Governor Deval Patrick, and Tom Grilk, Executive Director,...
Detailed view of a memorial on Boylston Street commemorating the two-year anniversary of the 2013 Boston Marathon bombings, on April 15, 2015 in...
Memorial stands at the site of the first bomb that went off in the Boston Marathon bombing of 2013 on January 4, 2015 in Boston, Massachusetts. Jury...
The funeral procession passes through town for 29-year-old Krystle Campbell, who was one of three people killed in the Boston Marathon bombings, on...
Musician plays patriotic tunes by a makeshift memorial for victims near the site of the Boston Marathon bombings at the edge of the still-closed...
In this image released by the Federal Bureau of Investigation on April 18 two suspects in the Boston Marathon bombing walk near the marathon finish...
Police cordon off the area in front of the White House in Washington, DC, on April 17, 2013 following attacks at the Boston marathon. US President...
Investigators in white jumpsuits work the crime scene on Boylston Street following yesterday's bomb attack at the Boston Marathon April 16, 2013 in...
Three Boston shirts lay on a barricade at a memorial site at Boylston and Arlington streets along the course of the Boston Marathon on April 16 a few...
Boston police officer stands guard at a memorial site at Boylston and Arlington streets along the course of the Boston Marathon on April 16 a few...
View of the back side of the finish line at the Boston Marathon where several explosions rocked the event sending over 100 people to local hospitals...
