BOSTON — Jury selection in the federal death penalty trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev is going slower than expected. Here's what you need to know as the trial enters its third week:

THE CASE:

Tsarnaev, 21, is charged in a deadly terror attack on the 2013 Boston Marathon. Two pressure-cooker bombs placed near the finish line killed three people, including an 8-year-old boy, and injured more than 260. Prosecutors say Tsarnaev and his older brother, Tamerlan, planted and detonated the bombs in retaliation for U.S. wars in Muslim countries. Tamerlan Tsarnaev died in a shootout with police several days after the bombings.

JURY SELECTION:

Individual questioning of prospective jurors began last week, and Judge George O'Toole Jr. originally said he would question 40 people each day. But only 34 people were questioned during the first two days. More than 1,350 people have filled out juror questionnaires.

Prospective jurors are called into the courtroom in groups of about 20 and given initial instructions from the judge. O'Toole has told potential jurors that they will decide whether Tsarnaev lives or dies. Seventeen of the 30 charges against Tsarnaev are capital crimes punishable by death. Tsarnaev sits at a large table, surrounded by his lawyers and across the table from prosecutors. The judge sits near the prospective jurors and does most of the questioning. The judge has been allowing prosecutors and Tsarnaev's lawyers to ask follow-up questions.

THE DEFENDANT:

Tsarnaev's curly hair was long and unkempt during the first phase of jury selection. He also had a scruffy beard. When individual questioning started, Tsarnaev had a haircut, and his beard was neatly trimmed. He spent much of the time looking down and drawing on a legal pad and occasionally looked at jurors as they were questioned.

PROSPECTIVE JURORS:

Many of the 34 people questioned so far do not appear likely to be picked for the jury. Some have expressed strong opposition to the death penalty and said they could not impose it under any circumstances. Others have said the predicted three- to four-month trial would be a serious financial hardship. Still others said they have not formed an opinion about Tsarnaev's guilt and would be willing to consider both life in prison or the death penalty if he is convicted.

Some people had poignant responses that could keep them off the jury. One woman choked back tears when she spoke of Martin Richard, the 8-year-old Dorchester boy who was killed in the attack. A man said his wife is an intensive care nurse who treated people injured in the bombing. A woman said her husband is a state trooper and she would find it difficult to be impartial, given that Tsarnaev is also accused of killing an Massachusetts Institute of Technology police officer.

WHAT'S NEXT:

On Tuesday, the judge will bring in another group of prospective jurors for individual questioning. The process will continue each day until a group of 60 to 70 people have been qualified as potential jurors. After that, Tsarnaev's lawyers and prosecutors will be allowed to eliminate some people from juror consideration without stating a reason. A panel of 12 jurors and six alternates will be chosen. The judge has said he hopes to begin testimony on Jan. 26.