BOSTON — A surveillance video shows a man prosecutors say is Dzhokhar Tsarnaev placing a bomb near the finish line of the Boston Marathon, just yards from where an 8-year-old boy was killed when it exploded.
A hand-scrawled confession condemning U.S. actions in Muslim countries was found on the inside wall of the boat where Tsarnaev was captured four frantic days later.
A year after twin pressure-cooker bombs shattered the marathon and paralyzed the area for days, federal prosecutors say they have a trove of evidence ready to use against the surviving suspect, but many questions remain.
What roles did Dzhokhar Tsarnaev and his older brother, Tamerlan, allegedly play in planning and orchestrating the attack? Would they really have launched a second attack in New York? Did federal authorities underreact to a warning from Russia that Tamerlan Tsarnaev was becoming radicalized?
With Tamerlan Tsarnaev killed in a police shootout days after the attack, some of those questions may never be fully answered.
“The obvious one is the motivation and how could two young men who were in a country that, from all appearances, was very good to them end up this radical,” said former Boston Police Commissioner Ed Davis, who helped lead the investigation.
The bombings last April 15 killed three people and injured more than 260 near the finish line of one of the world’s most famous marathons. At least 16 of the victims lost limbs.
Dzhokhar has pleaded not guilty to a 30-count federal indictment that carries the possibility of the death penalty.
The brothers, ethnic Chechens who lived in the former Soviet republic of Kyrgyzstan and the Dagestan region of Russia, settled in Cambridge, outside Boston, after moving to the United States as children with their family more than a decade ago.
Dzhokhar’s defense team, which includes two of the nation’s top anti-death penalty lawyers, appears to be building a case that Tamerlan, 26, was the driving force behind the bombings. In court documents, they’ve focused on Dzhokhar’s young age — 19 at the time of the bombings — and the influence his older brother had on him.