Jurors begin the process of determining Dzhokhar Tsarnaev's fate on 30 federal charges connected to the deadly twin attacks.
Jurors have begun deliberating in the federal death penalty case of accused Boston Marathon bomber Dzhokhar Tsarnaev.
Tsarnaev faces 30 federal charges in connection with the 15 April 2013 bombings that killed 3 people and injured 264 others.
The 21-year-old is also charged in the fatal shooting of an MIT police officer days after the attacks.
If he is convicted, jurors will hear a 2nd round of evidence before determining whether to sentence Tsarnaev to death or life in prison.
In closing arguments on Monday, the prosecution urged the panel to hold Tsarnaev accountable for the attacks they said he carried out with his older brother in order to "punish America" for its wars in Muslim countries.
"This was a cold, calculated terrorist act," Assistant US Attorney Aloke Chakravarty told jurors.
"This was intentional. It was bloodthirsty. It was to make a point.
"It was to tell America that 'We will not be terrorised by you anymore. We will terrorise you.'"
Tsarnaev's lawyers, who acknowledged at the trial's outset that their client helped orchestrate the attacks, have tried to convince jurors that he was pressured by his radicalised older brother.
The surprise admission was part of the defence's effort to spare Tsarnaev the death penalty should the jury convict him, as expected.
Defence attorney Judith Clarke on Monday told jurors it was 26-year-old Tamerlan Tsarnaev who "built the bombs" and "murdered (MIT police) officer Collier".
"Tamerlan led and Dzhokhar followed," she said.
Tamerlan Tsarnaev was killed following a gun battle with police when his brother inadvertently ran him over with a car they had hijacked.
Robel Phillipos, a friend of suspected Boston Marathon bomber Dzhokhar Tsarnaev, who is charged with lying to investigators, leaves the federal courthouse after a hearing in his case in Boston
Over the last several weeks, the jury has heard testimony from friends and family of those killed in the attacks and from more than a dozen people who lost limbs as a result of the bombings.
Jurors even heard from police officers who described exchanging gunfire and dodging homemade explosive devices thrown by the Tsarnaev brothers as they attempted to flee the city.
The defence called just 4 witnesses over 2 days in presenting its case.
Tsarnaev's lawyers have not indicated whether he will testify during the sentencing phase.
Source: Sky News, April 7, 2015