19-year-old Dzhokhar Tsarnaev faces 30 charges linked to April's Boston marathon bomb blasts, which killed three people and inured 260 others.
A fourth victim, a policeman, was shot dead by him and his brother during the hunt for them, say federal prosecutors.
Seventeen charges could bring life in prison or even the death penalty, US prosecutors said.
Dzhokhar Tsarnaev's brother, 26-year-old Tamerlan, was killed in a shoot-out with police days after the twin blasts.
The explosives were described as pressure-cooker bombs, packed with shrapnel.
Dzhokhar Tsarnaev was injured in that gun battle and has been held in a prison hospital near Boston since his capture on 19 April.
The brothers are from a family of ethnic Chechen Muslims from Russia and had been living in the US for about a decade.
More top news
The victims, named as Jamonicka Johnson, Von Johnson Jr., Devonte Asberry, Venetia Asberry, and Lenda Asberry, drowned in Texas.
Tonight it'll become dry and clear for most parts of Britain.
More than 30 lions rescued from circuses in South America have arrived in Johannesburg to begin a new life at an African wildlife reserve.