Boston ( CNN ) A U.S. appeals court has rejected a fourth request to move the trial for the accused Boston Marathon bomber to another city . The death penalty trial of Dzhokhar Tsarnaev has been delayed by painstaking jury selection , crippling snowstorms and last-ditch appeals for change of venue . Earlier this month , Judge George O'Toole , along with the prosecution and defense teams , settled on a pool of 70 jury prospects after questioning 256 people over three weeks . Before the appeals court ruled Friday , the defense tried three times to persuade O'Toole to move the trial , claiming it could n't find an impartial jury in Boston . He refused . The attorneys will weed out jurors they believe are less sympathetic to their case next week . When that is done , the panel of 12 jurors and six alternates is expected to be formally seated to hear opening statements and the first witnesses to an event that cut Boston to its core . O'Toole indicated the trial could last well into June . The jurors first will decide whether Tsarnaev is guilty of using weapons of mass destruction to kill people at a large public event . If Tsarnaev is convicted , the jury then will decide whether he should be punished by life in prison without the possibility of release or death , most likely by lethal injection . Potential jurors were questioned at length about whether they believed Tsarnaev was guilty and whether they could consider the death penalty in a state where it has n't been an option in a generation . Massachusetts wiped the death penalty from its books for good in 1984 , and no one has been executed there since 1947 . But this case is being tried in federal court , and 17 of the 30 counts against Tsarnaev include the death penalty as a possible punishment . Also cited are so-called aggravating factors such as committing an act of terror and the tender age of the youngest person killed , 8-year-old Martin Richard . Many potential jurors said they thought Tsarnaev was guilty of the April 15 , 2013 , bombings , which killed three people near the finish line . He is also charged in the April 19 , 2013 , death of Massachusetts Institute of Technology police officer Sean Collier . The officer was ambushed in his patrol car and shot to death as Tsarnaev and his brother , Tamerlan , ran from police hours after their photographs were released to the public . Opening statements and the first witnesses originally were slated for January 26 , but it took longer than anticipated to question the prospective jurors . Many of the jury prospects struggled with questions about where they stood on the death penalty and whether they could follow the law and vote for capital punishment if the facts and the law led them to that decision . It is almost certain that the trial , which will include wrenching testimony and video footage of the bombing victims , will be well underway during the running of this year 's Boston Marathon on April 20 . Tsarnaev , 21 , is accused of building two homemade pressure cooker bombs with his brother . The bombs detonated within moments of each other near the finish line . Aside from the three deaths , more than 250 people were injured by flying shrapnel and nails . Several survivors lost limbs . Tamerlan Tsarnaev died during a gun battle with police , and Dzhokhar Tsarnaev was found hours later , bleeding and hiding in a boat in a Watertown backyard . He had written Islamist slogans on the sides of the boat , federal authorities allege . No cameras are allowed at the Tsarnaev trial . But CNN 's Ann O'Neill will be there every day . Think of her as The 13th Juror , bringing insights here weekly . And follow @ AnnoCNN on Twitter daily .
Trial of accused Boston Marathon bomber Dzhokhar Tsarnaev is set to begin next week . It 's been long delayed by various issues , including jury selection .