The Boston Marathon bomber's lawyers urged a federal court to overturn their client's death sentence, arguing Thursday that intense media coverage and signs of juror bias led to an unfair trial.
The three-judge panel didn't render a decision after hearing from both sides for about an hour each.
Dzhokhar Tsarnaev, who was convicted of all 30 charges against him, including conspiracy and use of a weapon of mass destruction, didn't attend the hearing. Tsarnaev, now 26, is in a supermax prison in Colorado.
A handful of survivors and their supporters sat silently in the 1st U.S. Circuit Court of Appeals room to observe the latest chapter in the April 15, 2013 attack, which killed three people and injured more than 260 others.
"I thought this was all over," Melida Arredondo remarked briefly as she left the courthouse.
She said she attended because her husband, Carlos, who had helped victims at the finish line, had been at every day of the 2015 trial but couldn't make it Thursday.
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Tsarnaev's lawyer Daniel Habib argued the trial should have been held in another city because of intense local media coverage and the emotional toll the attack had on the region.
But Judge William Kayatta noted that polling submitted by the defense ahead of the 2015 trial suggested that almost two-thirds of Boston-area residents hadn't decided whether they thought Tsarnaev deserved the death penalty.
He also said the poll's findings suggested there wasn't a great disparity in public opinion of the case in Boston over other cities where the trial could have been held, such as New York.
The appellate judges focused most of their attention on questions surrounding two jurors who were allowed to remain on the case, even after defense lawyers uncovered social media posts suggesting they harbored strong opinions.
In one instance, a juror published two dozen tweets after the bombings, including retweeting one after Tsarnaev's arrest that read: "Congratulations to all of the law enforcement professionals who worked so hard and went through hell to bring in that piece of garbage."
That juror, who would go one to become the foreperson, or chief spokesperson, had also tweeted about her family's experience sheltering in place along with thousands of other Greater Boston residents during the hunt for the bombers, Tsarnaev's lawyers said.
Another juror posted on Facebook as he was going through the jury selection process. His friends encouraged him to "play the part" in order to get on the jury and make sure Tsarnaev was convicted.
Images From Boston Marathon Bombing Trial
Tsarnaev's lawyers had raised the social media comments as reasons to disqualify the two jurors before the trial even started, but prosecutors downplayed them, and Judge George O'Toole allowed them to remain on the case.
Under the district court's rules, the trial judge was obligated to ask more detailed follow-up questions after the social media posts came to light, said Judge O. Rogeriee Thompson.
"The judge didn't ask anything of that juror, who was right in the building," Kayatta said at one point. "It's very puzzling."
Federal prosecutor William Glaser acknowledged O'Toole never asked the two jurors any follow-up questions, but he argued the judge took the concerns seriously at the time. O'Toole, he said, re-reviewed the transcripts of the jurors' prior interviews before making his decision.
"This isn't an instance of the court conducting no inquiry at all," Glaser said.
The appellate judges asked relatively fewer questions about the contention from Tsarnaev's lawyers that O'Toole wrongly excluded evidence connecting Dzhokhar's older brother, Tamerlan Tsarnaev, to a still-unsolved triple murder in Massachusetts in 2011, less than two years prior to the bombing.
During the 2015 trial, Dzhokhar Tsarnaev's lawyers did not dispute that their client was involved in the marathon attack.
But they had hoped to argue for a life sentence rather than death by demonstrating that 26-year-old Tamerlan Tsarnaev was radicalized, violent and the mastermind behind the attack, while his younger brother had merely followed along.
Tamerlan Tsarnaev was killed in a gun battle with police days after the brothers detonated two pressure cooker bombs near the marathon finish line.
If the sentence is overturned, prosecutors can seek a new death penalty trial or allow Tsarnaev to accept the life sentence his lawyers originally sought.
If the sentence is upheld, his lawyers have other options for appeal, including to the U.S. Supreme Court.
Robert Bloom, a Boston College law professor, said Tsarnaev's lawyers have a compelling case to make.
The death penalty trial of 1995 Oklahoma City bomber Timothy McVeigh was moved to Denver over similar concerns about impartiality, he noted.
"The Boston Marathon is in the very DNA of the city. It's like Fenway Park and Paul Revere's house," Bloom said. "And the bombing affected everyone. Everyone had to shelter in place. Everyone had those Boston Strong shirts."