Boston jury grappling with Tsarnaev's true identity

Last Updated Apr 8, 2015 2:55 PM EDT

Update: The jury found Dzhokhar Tsarnaev guilty of all charges in the Boston Marathon bombing.

Jury deliberations began Tuesday in the Boston Marathon bombing trial. Jurors are going over 16 days of testimony and evidence from the Boston courtroom. Five men and seven women will decide the fate of accused bomber Dzhokhar Tsarnaev in the attacks that left four people dead and more than 260 injured.

The jury ended its first day of deliberations without reaching a verdict.

Jury to get case in Boston bombing trial

This is the first time jurors were able to discuss the case and the 30 counts ranging from using weapons of mass destruction to conspiracy, reports CBS News correspondent Don Dahler.

Lawyers have painted clashing portraits of Tsarnaev.

Federal prosecutor Aloke Chakravarty didn't mince words when he described Tsarnaev and his actions in closing arguments Monday.

"This was a cold, calculated terrorist act. This was intentional. It was bloodthirsty. It was to make a point," Chakravarty said. "It was to tell America that we will not be terrorized by you anymore. We will terrorize you."

The jury saw video of Tsarnaev setting down his pressure cooker bomb right behind a row of children, including the youngest victim to die in the attack, 8-year-old Martin Richard.

"These children weren't innocent to him. They were American. Of all the places that he could have placed the bomb, he placed it right there," the prosecutor argued.

The government says evidence like the jihadi materials found in Tsarnaev's laptops and his alleged confession written while hiding in a boat prove that Tsarnaev was a willing partner in the bombings, the murder of officer Sean Collier, and the carjacking of Dun Meng.

The prosecution ended with a montage of graphic images from the aftermath of the attacks, accompanied by jihadi chants found on the defendant's mobile devices.

In her closing arguments, attorney Judy Clarke continued with the theme which has been at the heart of Tsarnaev's defense: he did it, but he was manipulated by his older brother, Tamerlan. She said evidence shows it was Tamerlan who bought the materials, built the bombs and lured the younger brother into jihad.

"We must understand who was leading and who was following," Clarke told the court. "We don't deny that Dzhokhar fully participated in the events. But if not for Tamerlan it would not have happened."

If a guilty verdict is handed down on any of the 30 counts, the sentencing phase would begin next Monday. If that verdict includes one of the death penalty charges, the same jury would hear evidence on whether Tsarnaev should get life in prison or face execution.