BOSTON (AP) -- Jurors in the trial of Boston Marathon bomber Dzhokhar Tsarnaev have resumed deliberations for a second day in the first phase of his federal death penalty trial.

The jury began their second day of deliberations Wednesday after Judge George O'Toole Jr. answered two questions they asked about the conspiracies Tsarnaev is charged with and the concept of "aiding and abetting."

Defense attorney Judy Clarke is depicted addressing the jury as defendant Dzhokhar Tsarnaev, right, sits during closing arguments Monday. (AP Photo/Jane Flavell Collins)

Tsarnaev's lawyer admitted he participated in the 2013 attack but said his now-dead brother, Tamerlan, was the mastermind.

If Tsaranev is convicted, the same jury will hear evidence to decide whether he is sentenced to death or life in prison.

Three people were killed and more than 260 were injured when twin pressure-cooker bombs exploded near the marathon finish line in April 2013.

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