Dzhokhar Tsarnaev is on trial for his life in a Boston courtroom, and his legal team began his defence on Wednesday with an admission of guilt.
Attorney Judy Clarke said of her client during opening statements in the Boston Marathon bombing trial: "It was him."
It is the first time such an admission has been made.
The strategy established on day one by Tsarnaev's defence team, then, is that he was swept up in his older brother's actions throughout the bombing and its aftermath, which resulted in Tamerlan Tsarnaev's death in a shootout with police.
"It was Tamerlan who self-radicalised," Clarke said. "It was Dzhokhar who followed."
The younger Tsarnaev is facing 30 counts related to the terror that swept Boston over four days in April 2013 and resulted in the deaths of four people. An additional 260 people were injured in the Patriots' Day attack.
With the basic facts of what happened on Boylston Street apparently not in dispute, Tsarnaev's defence appears focused on avoiding the death penalty for the 21-year-old.
If the jury finds Tsarnaev guilty, it will have only two sentencing options — death or life in prison.
The last execution in Massachusetts took place and 1947 and the state eliminated the death penalty more than 30 years ago, but Tsarnaev would be subject to a death sentence because he is being tried in a federal case.
Only three federal prisoners have been executed since capital punishment was reinstated in 1976.