BOSTON — Two dramatically different portraits of Boston Marathon bombing suspect Dzhokhar Tsarnaev are expected to emerge when prosecutors and Tsarnaev’s lawyers give their opening statements at his federal death penalty trial.

Was he a submissive, adoring younger brother who only followed directions given by his older, radicalized brother? Or was he a willing, active participant in the attacks?

The trial that begins Wednesday is expected to be one of the most closely watched terror cases in years.

Tsarnaev’s lawyers have made it clear they will try to show that at the time of the bombings, Tsarnaev, then 19, looked up to his older brother, Tamerlan, 26, and was heavily influenced by him. They plan to portray Tamerlan as the mastermind of the attack. He died following a shootout with police days after the bombings.

But prosecutors say Dzhokhar was an equal participant who acted of his own free will. He faces 30 charges in the bombings and the fatal shooting days later of a police officer from the Massachusetts Institute of Technology. Seventeen of the charges carry the possibility of the death penalty.