Boston Bombing: In Closing Arguments, Contrasting Images Of Tsarnaev

Updated at 5:16 p.m. ET

Prosecutors and lawyers for Dzhokhar Tsarnaev made their closing arguments Monday, the final step before the jury decides whether to convict the accused Boston Marathon bomber.

"There was nothing about this day that was a twist of fate," Assistant U.S. Attorney Aloke Chakravarty told the jurors. "This was a cold, calculated terrorist act. This was intentional. It was bloodthirsty. It was to make a point. It was to tell America that 'We will not be terrorized by you anymore. We will terrorize you.'"

That view was countered by Tsarnaev's defense. Attorney Judy Clarke said there would have been no attack if it hadn't been for Tsarnaev's older brother, Tamerlan.

"We don't deny that Dzhokhar fully participated in the events, but if not for Tamerlan, it would not have happened," Clarke said.

Three people were killed and 264 others wounded — some severely — when pressure-cooker bombs went off during the Boston Marathon on April 15, 2013.

Tsarnaev was charged with 30 counts, and he's expected to be found guilty of most of them. The jury begins its deliberations on Tuesday.

NPR's Tovia Smith reported last week:

"Tsarnaev's lawyers have admitted he did what he's accused of doing. Their single aim is to try to cast Tsarnaev as less in charge than his brother Tamerlan — who died while they were running from authorities — and therefore less deserving of the death penalty if it gets to that."

The defense rested its case last Tuesday, after calling four people to testify; the prosecution had called 92.

Among the defense's witnesses was an FBI fingerprint expert who testified that pieces of the bomb showed only Tamerlan's prints; not Dzhokhar's. That was also true with the bomb that exploded in a firefight days later. The Tupperware bomb found after the shootout had prints from both brothers, but more from Tamerlan.

Another witness, a computer expert, testified that Tamerlan's computer was used to search for fireworks, detonators and gun stores. Dzhokhar's was used mainly for social media. Bomb-making instructions on Dzhokhar's laptop were transferred from his brother's computer, the computer expert testified.

If the jury does convict Tsarnaev, its members will then have to decide whether to put him to death. That's when, as Tovia reported, "this picture of Tsarnaev as young, vulnerable, intimidated by his older brother will really be drawn by defense attorneys who are hoping to convince jurors to spare Tsarnaev's life."

Tovia is covering the trial and is live-tweeting the proceedings. You can see those here:

You can also follow member station WBUR's live tweeting of the trial: