Updated

The American Civil Liberties Union says it's concerned about investigators' plans to interrogate the surviving Boston Marathon bombing suspect without reading him his Miranda rights.

The Massachusetts Federal Public Defender's office says it will take the case of 19-year-old bombing suspect Dzhokhar Tsarnaev. Public defender Miriam Conrad says there are "serious issues" regarding the interrogation.

But it's not clear when Tsarnaev will be able to answer questions. He's hospitalized in serious condition and under heavy guard after being arrested Friday night following a daylong manhunt punctuated by gunfire.

The capture came at the end of a tense Friday that began with his 26-year-old brother Tamerlan dying in a gunbattle with police.