Jurors in the trial of Boston Marathon bomber Dzhokhar Tsarnaev are deliberating for a second full day Friday on whether he should be sentenced to life in prison or the death penalty.
The jury of seven women and five men deliberated about 8½ hours Wednesday and Thursday without reaching a verdict.
As they work, jurors must fill out a lengthy, complicated verdict form that asks them to make findings on 12 aggravating factors prosecutors say support a death sentence and 21 mitigating factors his lawyers say support a decision to instead sentence him to life in prison.
The jurors must weigh any mitigating factors they find against any aggravating factors to determine Tsarnaev's sentence.
Seventeen of the 30 charges Tsarnaev was convicted of carry the possibility of the death penalty.
Three people were killed and more than 260 were injured when two pressure cooker bombs packed with shrapnel exploded near the marathon finish line on April 15, 2013.
Prosecutors told the jury Tsarnaev is a remorse-free terrorist who bombed the marathon to retaliate against the U.S. for wars in Muslim countries. His lawyers say he was a "good kid" who was led down the path to terrorism by his radicalized older brother.
The verdict form walks jurors through a process before they get to the decision on whether Tsarnaev is sentenced to death or life in prison.
First, the jurors must decide whether any "gateway," or threshold, factors exist, including whether Tsarnaevintentionally killed the victim or victims; inflicted serious bodily injury that resulted in death; participated in an act contemplating that the life of a person would be taken; or engaged in an act of violence knowing that it created a grave risk of death so that it constitutes reckless disregard for human life.
Then, they must begin deciding on the various mitigating and aggravating factors.
It isn't until page 21 of the form that the jury is asked to check off what Tsarnaev's sentence will be.