Lawyers for Boston Marathon bomber Dzhokhar Tsarnaev are due in court on Tuesday to seek a new trial for their client, who was sentenced to death in June for the 2013 bomb attack that killed three people and injured more than 260.

U.S. District Judge George O'Toole agreed last month to hear defense attorneys' arguments about a federal sentencing law that applied additional prison time for crimes committed while in possession of a firearm. The Supreme Court found it overly broad two days after Tsarnaev was sentenced to death by lethal injection.

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Defense lawyers are also asking that rules put in place ahead of the trial providing them with privacy to communicate with their client be left intact as they prepare for appeal.

The defense in August asked that Tsarnaev be re-tried outside Boston, saying the intense publicity surrounding the attack and the trial unfairly influenced the 12 jurors who found their client guilty and sentenced him to death.

Tsarnaev, 22, is being held at the "Supermax" high security prison in Florence, Colorado, while his attorneys appeal his death sentence. He is not expected to be present in court, according to a spokeswoman for federal prosecutors.

He was last seen in public on June 24, when he said he was "sorry for the lives I have taken." His older brother, Tamerlan, who participated in the April 15, 2013 attack, died following a gun battle with police three days after the bombing.

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In addition to killing three people with homemade pressure-cooker bombs that the brothers learned to make from an al Qaeda publication, the two shot dead a university police officer as they tried to flee the city.

Martin Richard, 8, Chinese exchange student Lingzi Lu, 26, and restaurant manager Krystle Campbell, 29, died in the bombing. Three days later the Tsarnaevs shot dead Massachusetts Institute of Technology police officer Sean Collier, 26.

The legal wrangling over Tsarnaev's fate could play out for years, if not decades. Just three of the 74 people sentenced to death in the United States for federal crimes since 1998 have been executed.