Security personnel along Boylston Street near the finish line of the 119th Boston Marathon, April 20, 2015. [Photo/Agencies]

WASHINGTON - The life-or-death phase in the trial of Boston Marathon bomber Dzhokhar "Jahar" Tsarnaev began Tuesday, less than two weeks after prosecutors convicted Tsarnaev on all 30 counts tied to the 2013 deadly blasts.

Federal prosecutor Nadine Pellegrini introduced a new photo Tuesday, which showed Tsarnaev giving his middle finger to a security camera in his jail cell three months after the attack. Pellegrini said that it proves what type of the 21-year-old man is and why he should get the death penalty.

"Jahar Tsarnaev was and is unrepentant, uncaring and untouched by the havoc and sorrow that he has created," Pellegrini said in a Boston court. "He was willing to cross every line for glory and reward."

Tsarnaev was convicted earlier this month of all 30 charges against him during the trial's guilt-or-innocence phase. On Tuesday's phase, the same jury began the final phase of the trial to figure out whether he could get death or be sentenced to life in prison.

Pellegrini's presentation was followed by victims' impact statement starting with Celeste Corcoran, who made her way to the stand on two artificial limbs. She was waiting for her sister by the marathon finish line when the bombs went off within 12 seconds of one another.

"I remember hearing just blood-curdling screams. I just remember looking around and seeing blood everywhere," Corcoran said.

Corcoran said her husband, Kevin, immediately began applying pressure to her legs, then tied tourniquets using his belt and a belt he got from another man. "I just remember thinking how awful this was and how this had to stop. This couldn't be real, couldn't be real," she said.

After the prosecution witness ended, the defense will get a chance to present its case to keep their client alive. Tsarnaev's lawyers called four witnesses during the recent trial, compared to the 92 called by the prosecution.

His lawyers, who will make the case for mercy once the prosecution has put on its witnesses, are expected to portray Tsarnaev's brother Tamerlan as the mastermind of the bombing. They say Tsarnaev was a 19-year-old who fell under the evil influence of his domineering brother, who died in a confrontation with police after the bombing.

However, prosecutors contend Tsarnaev was a full partner with his brother and deserves the ultimate punishment.

"Jahar Tsarnaev was determined and destined to be America's worst nightmare," Pellegrini said, "His heart was full of rage."

On April 15, 2013, two bombs went off near the finish line of the Boston Marathon, killing three people and wounded more than 260 others. Dzhokhar Tarnaev and his 26-year-old brother Tamerlan Tsarnaeve were alledgedly behind the deadly bombing attacks.