Lawyers for Boston Marathon bomber Dzhokhar Tsarnaev are heading to court to urge a judge to grant him a new trial.
Three people were killed and more than 260 others were injured when twin bombs placed near the marathon finish line exploded on April 15, 2013.
Tsarnaev was convicted of 30 federal charges and sentenced to death for his role in the attack.
Tsarnaev's lawyers argue that a Supreme Court ruling in June puts 15 of his convictions in jeopardy.
The ruling centered on the legal definition of a "crime of violence," a distinction that can carry stiffer penalties.
The court struck down part of the definition as unconstitutionally vague.
They also say he should get a new trial to decide his punishment because the jury's imposition of the death penalty on other counts likely was influenced by the 15 counts related to crimes of violence.