Lawyers for Boston Marathon bomber ask Supreme Court to deny government request to review appellate ruling tossing death penalty

Lawyers for Boston Marathon bomber Dzhokhar Tsarnaev on Thursday asked the US Supreme Court to deny a request from prosecutors to review a July appeals court ruling that vacated his death sentence in the high-profile case.

Thursday’s filing came in response to a formal request, known as a petition for a writ of certiorari, that prosecutors filed with the court in October asking the panel to review the matter.

Justice Department lawyers are seeking review of the ruling issued July 31 by the US Court of Appeals for the First Circuit. The appeals court overturned Tsarnaev’s death sentence, finding the judge who presided over his 2015 trial in US District Court in Boston failed to question prospective jurors thoroughly about their exposure to pretrial publicity in the case.

The appeals court also found the judge improperly refused to allow Tsarnaev’s attorneys to present evidence to jurors indicating Tamerlan Tsarnaev, his older brother and accomplice in the bombings, had allegedly murdered three people in Waltham in 2011 and recruited a friend to join him in that crime.

“That evidence went to the heart of respondent’s [Dzhokhar’s] mitigation case because it showed Tamerlan’s planning of extreme violence and his ability to influence others to join him in those acts,” Dzhokar Tsarnaev’s lawyers wrote.

The Tsarnaev brothers set off two pressure cooker bombs near the marathon finish line on April 15, 2013, killing three people, including an 8-year-old Dorchester boy, and wounding hundreds more. The brothers also fatally shot an MIT police officer on April 18, 2013, while they were on the run.

Tamerlan Tsarnaev was killed in a gunfight with police in Watertown several days after the blasts. A Boston police officer died a year later of head injuries sustained during the confrontation.

In seeking high court review of the appellate court ruling tossing Dzhokhar Tsarnaev’s death sentence, prosecutors wrote in their October filing that the younger sibling was a willing participant in the bombings who read radical Islamic literature, expressed an interest in jihad and martyrdom, and showed no remorse or inclination to disassociate from his older brother following the attack.

Dzhokhar Tsarnaev’s lawyers on Thursday also zeroed in on the First Circuit’s findings on the questioning of prospective jurors about their exposure to the onslaught of pretrial publicity.

The trial judge, the filing said, rather than probe prospective jurors’ exposure to the coverage in the news and on social media, deferred “instead to their untested assurances of impartiality. ... The district court seated one prospective juror who dissembled about calling respondent a ‘piece of garbage’ and sheltering in place, and another who hid a friend’s suggestion to ‘play the part,’ ‘get on the jury,’ and send respondent ‘to jail where he will be taken care of.’ ”

Tsarnaev, 27, remains incarcerated at a federal supermax prison in Colorado. The July ruling from the appeals court granted him a new trial for the sentencing phase only. He’ll die in custody either after serving a life sentence or by execution, whether the Supreme Court agrees to review the case or not, according to legal filings.