Reuters – Attorneys for accused Boston Marathon bomber Dzhokhar Tsarnaev and federal prosecutors who say he killed four people are due to make their closing statements on Monday before a jury begins deliberations on whether he is guilty of the attack in 2013.

But a month after defense lawyers bluntly admitted the 21-year-old's role in the bombing and the four chaotic days that followed it, each side's focus will be less on guilt than on the question of whether Tsarnaev will die for his crimes.

The first half of Tsarnaev's trial in Boston federal court proceeded at a blistering pace, with the two sides making their case in just 16 days, less time than it took to select the jury.

That speed reflects the fact that the defense was not able to make its primary argument, that Tsarnaev was a junior partner in a scheme hatched and largely carried out by his 26-year-old brother Tamerlan, who died following a gunfight with police four days after the bombing.

Blocked from making that case until after Tsarnaev is found guilty, defense attorneys opted to cross-examine less than half the prosecution's witnesses and called just four of their own.

Monday's closing statements could be a preview of the arguments each side plans to make during the next phase of the trial, when the same jury will hear a fresh round of witness testimony before determining whether to sentence Tsarnaev to life in prison without possibility of parole, or to death.

"The rules of evidence are severely relaxed during the penalty phase of a capital trial and much more open to any sort of mitigating evidence of any sort that limits the defendant's responsibility," said Peter White, a lawyer at Schulte Roth & Zabel in Washington and former federal prosecutor.

Witnesses in the trial so far have testified that Dzhokhar Tsarnaev's fingerprints were not found on bomb-making material at his brother's Cambridge, Massachusetts, apartment and that extremist literature found on his computer, including copies of Al Qaeda's "Inspire" magazine, had initially been downloaded by Tamerlan.

The jury also saw images of Dzhokhar Tsarnaev standing with a backpack in the crowd at the marathon's finish line minutes before the blasts that killed restaurant manager Krystle Campbell, 29, Chinese exchange student Lingzi Lu, 23, and 8-year-old Martin Richard. Tsarnaev is also accused of the fatal shooting of Massachusetts of Institute of Technology police officer Sean Collier, 26.

The jury has yet to hear from Tsarnaev, though it has so far heard from friends and family of those who were killed, from 17 people who lost limbs in the attack, and from emergency responders, including a police officer who described wrestling with Tamerlan in his final moments.

The defendant has sat quietly in court through the proceedings and has generally avoided looking at witnesses.

But if he is found guilty, he may testify during the sentencing phase of his trial, legal experts said.

"He is fighting for his life at this point in time. What has he got to lose?" said David Weinstein, an attorney at Clarke Silverglate in Miami, who brought death penalty cases when working as a state and federal prosecutor.

"If you can put the client on the stand and humanize him and get the jurors to understand this is a life worth saving, then he needs to testify."

While you were sleeping, this also happened...