Attorneys trying to overturn the death sentence of convicted Boston Marathon bomber Dzhokhar Tsarnaev say in a new court filing that the 2013 explosions so traumatized the region that it was impossible to get an impartial jury.

The Boston Globe reports that Tsarnaev's lawyers say his rights to a fair trial were violated because the jury that voted to sentence Tsarnaev to death was from drawn from a pool of people, nearly all of whom were familiar with the broad details of the attack.

They also say 69% of the jury pool believed Tsarnaev was guilty.

Tsarnaev was convicted of carrying out the April 15, 2013, attack with his older brother, who was killed by authorities. He is appealing the death sentence.

Prosecutors maintain an impartial jury was carefully selected.