BOSTON - The jury in the Boston Marathon bombing trial on Friday heads into its third day of deliberations on whether Dzhokhar Tsarnaev is sentenced to death or to life in prison without the possibility of release.
Tsarnaev, a 21-year-old ethnic Chechen was convicted last month of killing three people and injuring 264 others by detonating a pair of homemade pressure-cooker bombs at the race's crowded finish line on April 15, 2013.
Three days later, he and his 26-year-old brother shot a police officer to death, setting off 24 hours of chaos in which the pair carjacked a Chinese businessman and hurled bombs at police, triggering a daylong lockdown of most of the Boston area while police searched for Tsarnaev.
Federal prosecutors contend that Tsarnaev, who moved with his family to Cambridge, Massachusetts, from Russia a decade before the attack, was an adherent of al Qaeda's militant Islamist ideology who wanted to "punish America" with the attack.
Defence attorneys, meanwhile, portrayed him as a hapless teenager who was in the thrall of his older brother, Tamerlan, who they contend dreamed up the attack after being spurned by a militant group he had attempted to join on a 2012 trip to Russia.
Tamerlan died in the early morning hours of April 19, 2013, after a gunfight between the brothers and police in suburban Watertown, Massachusetts, that ended when Dzhokhar ran Tamerlan over with a stolen car.
During the trial the jury saw gruesome, sometimes graphic, videos of the explosions and their bloody aftermath and heard from some of the 18 people who lost limbs in the bombing, as well as friends and family of the four people killed by the Tsarnaevs.
Eight-year-old Martin Richard, 23-year-old Chinese exchange student Lingzi Lu and 29-year-old restaurant managed Krystle Campbell died in the bombing. Massachusetts Institute of Technology police officer Sean Collier was shot dead by the Tsarnaevs three days later.