The Boston Marathon bombing was the deadliest act of terrorism in the U.S. since the Sept. 11 terrorist attack, and the trial is one that many have been waiting for.
A couple dozen survivors are expected in court for at least part of the trial — including Heather Abbott, who lost a leg in the attack. She's hoping for answers to both why and how the bombing was carried out.
"Things like how did bomb arrive? Was it on the T? Did they drive it in a car? That may not mean a lot to other people but my leg is gone, and I think a lot about all the details," Abbott says.
Three bystanders and one police officer were killed in the blast and the aftermath, and hundreds were injured. Prosecutors have said the city of Boston itself was a victim of the bombing. That's why the defense wanted the trial moved somewhere else.
Former federal judge Nancy Gertner says it is gonna be extremely difficult to find impartial jurors given how many people were personally affected by the blast in 2013.
"Anyone on the finish line, anyone who had anybody running in race, anyone who was locked down while Tsarnaev was being apprehended, anyone who was told to stay in their house because a dangerous criminal was outside — all people in that category are people who felt vulnerable to the crime. There are categories that we would never in ordinary case say should sit on a jury.
Jury selection is expected to take several weeks. After that, the trial may well feel like the easy part. Prosecutors have amassed reams of evidence against Tsarnaev — from bomb making materials, and online instructions he allegedly used, to the note he allegedly scribbled in the boat where he was hiding — suggesting the attack was meant as retaliation for Muslims killed in Iraq and Afghanistan.
There is also video from the scene that U.S. Attorney Carmen Ortiz says further corroborates the case against Tsarnaev.
"Dzhokhar Tsarnaev placed a backpack containing a kind of IED among a crowd of marathon spectators including dozens of men, women and children," Ortiz says.
"This case is not about guilt," says Northeastern University law professor Daniel Medwed. "In my mind, this case is really about whether or not he's going to get the death penalty."
Medwed says defense attorneys appear to be building a case that Tsarnaev's life should be spared because he was acting, in a way, under duress; terrified of his older brother, and alleged co-conspirator Tamerlan Tsarnaev.
Medwed says the sentencing phase may be the longer and newsier part of the trial. "Were gonna learn a lot about Dzhokhar's background, about his beliefs, about his upbringing, about his relationship with his brother. We're going to learn more about Tamerlan than we've ever learned before," Medwed says.
But that focus on the suspects, is one reason some are still holding out hope for a plea bargain.
Former judge Nancy Gertner says an 11th hour deal could spare everyone the expense and trauma of trial. Prosecutors could present their evidence more quickly and the sentencing phase would be focused primarily on victims.
Gertner points to Sept. 11 conspirator Zacarias Moussaoui, shoebomber Richard Reid and Unabomber Ted Kaczynski, who all pleaded guilty in exchange for life in prison. A death sentence brings years of appeals, but a plea deal she says would offer more closure.
"The case is over. Tsarnaev is no longer in the press. The newspapers are not recounting countless appeals. It's over, and we don't hear of them anymore," Gertner says.
It's unknown if either prosecutors or Tsarnaev might be open to the idea. The most we've heard from the defendant, so far, is that he thinks his lawyers are doing a very good job on his behalf.