Tsarnaev, now 21 and facing 30 federal charges, ‘awkward’ during jury selection proceedings which will whittle down 3,000 potential jurors to 12

Bright winter sunshine drenched the John Joseph Moakley district court building in Boston as the trial of Dzhokhar Tsarnaev, accused of involvement in the Boston Marathon bombing in April 2013 that killed three people and injured more than 260 others, began on Monday morning.

Tsarnaev, who is now 21, entered the courtroom awkwardly, in white jeans and a dark sweater. Wearing no handcuffs, he reclined, his legs splayed wide beneath the table. For most of the judge’s address, he leaned on his elbows or clasped his hands tightly in front of him.

His face remained impassive throughout the proceedings; it was impossible to detect in his bearing either remorse or its absence. When called upon to stand up, he did so slowly and awkwardly.

Tsarnaev faces 30 federal charges including “conspiracy to use a weapon of mass destruction resulting in death”. Crucially, 17 of those carry a potential death sentence.

Monday marked the beginning of perhaps the most critical part of the entire trial – the selection of the jury which will hear the case.

Over the course of the next three days, in groups of 200-250 taken from a pool of 3,000, potential jurors will be addressed by the judge, and asked to fill out a questionnaire which will be reviewed both by the prosecution and the defence.

From this unusually large pool, a 12-person jury and six alternates will be selected.

The contents of the questionnaire were closed to the press, but according to court documents it contained around 100 questions designed to “determine the extent to which potential jurors have been affected in ways in which the defendant is concerned”.

Those jurors who are not whittled down by the questionnaire stage will next go through a process of “voir dire”, in which they take oral questions from the attorneys.

Addressing the first batch of potential jurors, in a speech that he is scheduled to give at least five more times in the next three days, Judge George O’Toole said that the jury’s duty was “to serve fairly and impartially”.

This, he said, “means to base a decision on what you hear in court, not on any possible bias, prejudice, or anything you have seen, heard or read outside the courtroom – including anything you … have learned in the media”.

He instructed the jurors not to read, watch or listen to any reports on this case in the news, or do any online research.

The defence has raised the question of whether it is possible for Tsarnaev to receive a fair trial in Boston, as the scale of the attack and its local impact means that it may be next to impossible to find a truly impartial jury – the phrase they used in their motion was “nearly universal local victimisation”. But repeated requests to move the trial to federal courts in other states have been denied.

Another key issue in jury selection is that of the death penalty. The state of Massachusetts has not had capital punishment since 1982, when a court declared it unconstitutional. A Boston Globe poll in September 2013 found that residents favoured life imprisonment over execution for Tsarnaev, 57% to 33%.

Part of the selection process will involve striking potential jurors who profess strong feelings about the death penalty.

“The judge will seek to eliminate those who are categorically opposed to the death penalty in all cases and those who believe that if there’s a conviction for capital murder, they must impose the death penalty,” Professor Ira Robbins of American University’s Washington College of Law told NBC News.

If Tsarnaev is found guilty on any of the capital charges, a secondary phase using the same jury will be triggered, in which the jury – not the judge – will decide whether to sentence Tsarnaev to death. This decision must be unanimous; if the jury cannot agree, the judge will step in to impose a sentence of life without parole.

Judge O’Toole said that once the jury selection process is complete, the trial will begin “on or around” 26 January and go on for “three or four months”.