WASHINGTON, Jan. 5-- The trial of accused Boston Marathon bomber Dzhokhar Tsarnaev began on Monday with the start of election for a 12-person jury and six alternates, an important process that could set the tone for the high-profile death penalty case.

According to court sources, Tsarnaev is accused of helping plan and carry out two bombings near the finish line of the Boston Marathon on April 15, 2013, with his elder brother, Tamerlan Tsarnaev.

The bombing killed three bystanders and wounded more than 260, dominating news in the United States and around the world for weeks. Dzhokhar Tsarnaev was taken into custody a few days later, after a manhunt that resulted in his brother's death.

Dzhokhar Tsarnaev was in the courthouse in South Boston on Monday to face 200 potential jurors, the first group of about 1,200 eastern Massachusetts residents who will be vetted to see if they can impartially judge Tsarnaev. Ultimately, they could have to determine if he is sentenced to death.

The trial, possibly the most high-profile federal death penalty case since the 1997 trial of Oklahoma City bomber Timothy McVeigh, is expected to last for several months. Jury selection could also take a few weeks until the end of January.

According to Judge George Toole, in the first stage of jury selection, potential jurors will fill out questionnaires, answering a series of questions designed to root out basic biases or conflicts of interest.

Toole has twice denied defense motions to relocate the trial, meaning jurors will be drawn from eastern Massachusetts. If 18 jurors cannot be selected from the initial pool of 1,200, hundreds more could be called.

Dzhokhar Tsarnaev made his first court appearance in July 2013, and pleaded not guilty to 30 charges for his alleged role in the bombings.