BOSTON — Boston Marathon bomber Dzhokhar Tsarnaev’s lawyers urged a jury Monday to spare his life, portraying him as “a good kid” who was led down the path to terrorism by his increasingly fanatical older brother.

David Bruck delivered the defense’s opening statement in the penalty phase of Tsarnaev’s trial, saying there is no punishment Tsarnaev can get that would be equal to the suffering of the victims.

“There is no evening the scales,” Bruck said. “There is no point in trying to hurt him as he hurt because it can’t be done.”

Tsarnaev, 21, was convicted of 30 federal charges in the twin bombings that killed three spectators and wounded more than 260 other people near the marathon’s finish line on April 15, 2013. He was also found guilty of killing an MIT police officer during the Tsarnaev brothers’ getaway attempt.

This stage of the trial will determine whether he is executed or spends the rest of his life behind bars.