The surviving Boston bomber, Dzhokhar Tsarnaev, was on Friday moved to a federal prison facility that provides specialised and long-term medical care.
The prison, at Fort Devens in Massachusetts, also holds Raj Rajaratnam, the Sri Lankan-born equity fund owner convicted of insider trading in 2011.
Tsarnaev had been held and interrogated at a Boston hospital since his arrest on April 19. He cooperated with the interrogators for 16 hours until he was read his rights.
He has since clammed up, according to US media reports.
But he had by then given away some crucial information, including the plan to drive to New York and detonate leftover explosives in Manhattan’s Times Square.
Within hours of the FBI releasing their pictures, on April 18, the Boston bombers set out for New York in a Mercedes SUV snatched from its owner.
But they were forced to dump their plan when they realised that the SUV had not enough fuel for the 330-km drive.
“Questioning of Dzhokhar revealed that he and his brother decided spontaneously on Times Square as another target,” New York police chief Ray Kelly told a news conference on Thursday.