The jury that convicted Dzhokhar Tsarnaev for the Boston Marathon bombing gathered Tuesday to begin figuring out how he should be punished. Will Tsarnaev be sentenced to die by lethal injection? Or will he be sentenced to life in prison without parole?

Adding to the uncertainty, even as federal prosecutors are preparing to argue in the coming weeks that he should be put to death, some families of victims and other survivors of the bombings have spoken out in recent days and asked that Tsarnaev not be executed.

The death penalty issue suffused the initial phase of the trial, particularly because Tsarnaev’s attorneys made no attempt at disputing his guilt. “It was him,” his defense attorney said during the opening statements in March. Lawyers on both sides agreed that Tsarnaev brought a bomb to Boylston Street during the marathon two years ago, making a guilty verdict inevitable.

Instead, the question of whether Tsarnaev could be put to death waited for the penalty phase of the trial, which began Tuesday at the federal courthouse in Boston.

Prosecutors made their opening statements in the morning, showing jurors and the others gathered in a federal courthouse an image of Tsarnaev, just months after he was captured, giving a camera a middle finger.

“This is Dzhokhar Tsarnaev: Unconcerned, unrepentant and unchanged,” Nadine Pellegrini, an assistant U.S. attorney, told the jurors, according to the Associated Press.

Tsarnaev has been found guilty on all 30 counts he faced, and 17 of these counts carry the death penalty. The government has said it is seeking the death penalty due to the “heinous, cruel and depraved manner” of the April 2013 attack, which killed three people and injured more than 260.

Yet in the days since the jury found Tsarnaev guilty, some of the people directly affected by the blasts asked the federal government to stop seeking the death penalty. The parents of Martin Richard, the 8-year-old boy killed in the bombing, wrote an open letter last week saying that a death sentence would only lead to years of appeals and prolong the case.

“We understand all too well the heinousness and brutality of the crimes committed,” William and Denise Richard said in their letter. “We were there. We lived it. The defendant murdered our 8-year-old son, maimed our 7-year-old daughter, and stole part of our soul.”

Martin Richard’s family, from left: Denise, his mother; Henry, his brother; Bill Richard, his father. (Charles Krupa/AP)

The Richards said that they supported the Justice Department dropping the death penalty in exchange for Tsarnaev spending his life in prison without parole or any right to appeal.

Patrick Downes and Jessica Kensky, newlyweds who each lost limbs in the attack, released a statement this week echoing the Richards.

“If there is anyone who deserves the ultimate punishment, it is the defendant,” they said in the statement, which was published by the Boston Globe. “However, we must overcome the impulse for vengeance.”

They said that the best possible outcome of the trial is making sure that Tsarnaev cannot hurt anyone and “that he disappears from our collective consciousness as soon as possible,” both of which they said would be accomplished if he were imprisoned for the rest of his life without parole or appeal.

Tsarnaev’s attorneys are expected to continue arguing that he was under the sway of his older brother, Tamerlan, who was killed in a shootout with police in the days after the bombing.

The only way Tsarnaev can be sentenced to death is if the jurors are unanimous. This made for an unusually tricky jury selection process, as Massachusetts has not had the death penalty for more than three decades.

It is unclear how the letter from Martin Richard’s parents will factor into the jury’s eventual decision. His age is an “aggravating factor” that has been cited by the prosecutors arguing for lethal injection. The federal death penalty statute notes that a very young or old victim can be deemed particularly vulnerable, and when prosecutors announced last year they would seek a death sentence, they noted Richard’s youth.

Prosecutors played a video of Tsarnaev placing one of the bombs near Richard during the trial, saying that the 8-year-old’s “entire body was shattered” in the blast. During the trial, William Richard gave an emotional testimony discussing how he found his son after the explosions. “When I saw Martin’s condition, I knew he wasn’t going to make it,” Richard said during his testimony.

In the years since the federal death penalty statute was reinstated in 1988 and expanded in 1994, three inmates have been put to death by the government, all of them by lethal injection. There are currently 61 inmates on federal death row, the Death Penalty Information Center reports.

A courtroom sketch of the closing arguments during the first phase of the trial. (Jane Flavell Collins/AP)

However, even when the government does seek a death sentence, judges and juries rarely impose it, having opted for a life sentence in about two-thirds of the trials, according to the Federal Death Penalty Resource Counsel Project.

A poll conducted last month in Boston for WBUR, the city’s NPR station, found that people in the region felt that Tsarnaev should be sentenced to life in prison (49 percent) rather than death (38 percent). Meanwhile, a nationwide poll conducted for CNN this month found that opinion was flipped, with more people arguing for the death penalty (53 percent) over life imprisonment (45 percent).

Overall, a majority of Americans support the death penalty, though that sentiment has been falling for two decades.