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...
Boston Police look at blown out windows at the scene of the first explosion on Boylston Street near the finish line of the Boston Marathon.
Runner embraces another woman on the marathon route near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15, 2013...
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. Victim...
Two officials run away from the first explosion, right, on Boylston Street at the 177th Boston Marathon, April 15, 2013.
In this image released by the Federal Bureau of Investigation on April 19 two suspects in the Boston Marathon bombing walk near the marathon finish...
Officials react as the first explosion goes off on Boylston Street near the finish line of the 117th Boston Marathon on April 15, 2013.
Police clear the bleachers after two explosions went off near the finish line of the 117th Boston Marathon on April 15, 2013.
In this image released by the Federal Bureau of Investigation on April 18 a suspect in the Boston Marathon bombing walks near the marathon finish...
Man comforts an injured woman on the sidewalk at the scene of the first explosion on Boylston Street near the finish line of the Boston Marathon.
Man is loaded into an ambulance after he was injured by one of two bombs exploded during the 117th Boston Marathon near Copley Square on April 15,...
Close-up of various objects, including flowers, running bibs, and American flags, at a memorial for the victims of the Boston Marathon Bombing ,...
Close-up of flowers around the base of a tree at a memorial for the victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts,...
Boston Marathon bombing hero Carlos Arredondo watches the New England Patriots Super Bowl victory parade on February 7, 2017 in Boston,...
Investigators in white jumpsuits work the crime scene on Boylston Street following yesterday's bomb attack at the Boston Marathon April 16, 2013 in...
An injured boy is pushed in a wheelchair by a Boston police officer at the scene of the first explosion near the finish line of the Boston Marathon.
Man is loaded into an ambulance after he was injured by one of two bombs exploded during the 117th Boston Marathon near Copley Square on April 15,...
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.
Athletic gear, including boxing gloves, skis, numerous sneakers and a basketball was found inside Tamerlan and Dzhokhar Tsarnaev, 3rd floor apartment...
Daily News front page April 24 Headline: KILLER DEAL - Bombers paid for lethal explosives - got 2nd set FREE - Tamerlan and Dzhokhar Tsarnaev used...
April Walton, manager of Phantom Fireworks store in Seabrook, New Hampshire, where Tamerlan Tsarnaev used a buy one, get one free coupon to buy two...
Daily News front page April 16 Headline: MASSACRE - At least 3 dead and 140 injured - A woman in tattered clothes looks on in shock amid carnage of...
Police block road after a campus police officer at Massachusetts Institute of Technology was shot near Building 32 during hunt for two suspects in...
Close-up of various objects, including flowers, a dreamcatcher, dog tags, and wind chimes, at a memorial for the victims of the Boston Marathon...
Close-up of flowers, including forsythia and a rose, in a plastic gallon jug at a memorial for the victims of the Boston Marathon Bombing , Copley...
View of people with umbrellas in a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston,...
Close-up of various objects, including flowers and American flags at a memorial for the victims of the Boston Marathon Bombing , Copley Square,...
Close-up of various objects, including T-shirts, flowers, rosaries, prayer flags, and a glow stick, at a memorial for the victims of the Boston...
Close-up of a plastic-covered message at a memorial for the victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9,...
View of a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9, 2013....
Close-up of various objects, including T-shirts, flowers, and American & Puerto Rican flags, at a memorial for the victims of the Boston Marathon...
Close-up of running shoes hanging on a plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May...
View of a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9, 2013....
Close-up of messages written on 'One Boston' leaflets and posted at a memorial for the victims of the Boston Marathon Bombing , Copley Square,...
Close-up of flower arrangements and American flags at a memorial for the victims of the Boston Marathon Bombing , Copley Square, Boston,...
View of a running shoe at the base of a plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts,...
View of a plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9, 2013.
Close-up of messages written on 'One Boston' leaflets and posted at a memorial for the victims of the Boston Marathon Bombing , Copley Square,...
Close-up of flowers and American flag, among other items, on and around a tree at a memorial for the victims of the Boston Marathon Bombing , Copley...
Close-up of various objects, including a T-shirt, flowers, rosaries, prayer flags, and a glow stick, at a memorial for the victims of the Boston...
View of a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9, 2013....
View of running shoes hanging on a plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9,...
View of various objects, including T-shirts, flowers, a paper crown, and American flags, on and around a tree at a memorial for the victims of the...
View of a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts, May 9, 2013.
View of people with umbrellas as they walk through a memorial for the victims of the Boston Marathon Bombing , Copley Square, Boston, Massachusetts,...
Exterior view of a house at 410 Norfolk Street, Cambridge, Massachusetts, April 21, 2013. The house was the residence of brothers Tamerlan and...
View, from behind, of two people with umbrellas as they read messages written on 'One Boston' leaflets and posted at a memorial for the victims of...
View of a statue of John Singleton Copley and, beyond it, a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing ,...
View of running shoes hanging on a partially enclosed, plastic-covered memorial to victims of the Boston Marathon Bombing , Copley Square, Boston,...
People observe a moment of silence near the Boston Marathon finish line on one week anniversary of the bombings on April 22, 2013 in Boston,...
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...
Investigators in white jumpsuits work the crime scene on Boylston Street following yesterday's bomb attack at the Boston Marathon April 16, 2013 in...
Emily Locher Weston, Connecticut looks out as runners pass near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15,...
Runners react near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15, 2013 in Boston, Massachusetts. Two people...
Runner reacts near Kenmore Square after two bombs exploded during the 117th Boston Marathon on April 15, 2013 in Boston, Massachusetts. Two people...
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...
Former Boston Red Sox designated hitter David Ortiz attends a finish line dedication ceremony in recognition of the ten-year anniversary of the...
