Lawyers for Boston Marathon bomber Dzhokhar Tsarnaev are heading to court to urge a judge to grant him a new trial.<br />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.<br />Tsarnaev was convicted of 30 federal charges and sentenced to death for his role in the attack.<br />Tsarnaev's lawyers argue that a Supreme Court ruling in June puts 15 of his convictions in jeopardy.<br />The ruling centered on the legal definition of a "crime of violence," a distinction that can carry stiffer penalties.<br />The court struck down part of the definition as unconstitutionally vague.<br />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.
