AKIPRESS.COM - Accused Boston Marathon bomber Dzhokhar Tsarnaev followed his older brother's lead in carrying out the 2013 bombing that killed three people, rather than acting on his own motivation, one of his attorneys argued on Monday, reports Reuters.

Tsarnaev, 21, could be sentenced to death if a jury finds him guilty of carrying out the April 15, 2013, attack and fatally shooting a police officer three days later as he and his brother, 26-year-old Tamerlan Tsarnaev, tried to flee the city.

Following the prosecution's closing argument, that the ethnic Chechen defendant was an extremist who had "wanted to punish America" with the bombing attack, Tsarnaev's lawyers argued that he had been in the thrall of his older brother.

Defense attorney Judith Clarke, who opened the trial last month by admitting that her client had committed all the crimes of which he is accused, repeated that assertion on Monday.

But in a counterpoint to the blunt "it was him" admission of her opening statement, Clarke told the jury that Tamerlan, who died four days after the bombing following a gunfight with police, had planned the attack and built the bombs. "Tamerlan did that," she said. "We need to understand who was leading and who was following."

By shifting some of the blame to the older brother, Tsarnaev's lawyers are trying to persuade the jury, if they find the defendant guilty, to sentence him to life in prison without the possibility of parole rather than death.

The jury on Monday also viewed video of Tsarnaev standing with a backpack in the crowd at the marathon's finish line minutes before the blasts that killed restaurant manager Krystle Campbell, 29, Chinese exchange student Lingzi Lu, 23, and 8-year-old Martin Richard.

Tsarnaev is also accused of the fatal shooting of Massachusetts of Institute of Technology police officer Sean Collier, 26.