Boston suspect moved from hospital

The facility, on the decommissioned Fort Devens US Army base, treats federal prisoners and detainees who require specialised long-term medical or mental health care.

The 19-year-old Tsarnaev is recovering from a gunshot wound to the throat and other injuries suffered during his attempted getaway.

The Massachusetts college student was charged with setting off the shrapnel-packed pressure-cooker bombs that killed three people and wounded more than 260 at the marathon finish line on April 15.

Earlier, officials said the suspects were headed for New York’s Times Square to blow up the rest of their explosives, in what they portrayed as a chilling, spur-of-the-moment scheme that fell apart when the brothers realised the car they had hijacked was low on fuel.

New York City Police Commissioner Raymond Kelly said Dzhokhar Tsarnaev told interrogators from his hospital bed that he and his older brother Tamerlan had decided spontaneously last week to drive to New York and launch an attack.

In their stolen sport utility vehicle they had five pipe bombs and a pressure-cooker explosive like the ones that blew up at the marathon.

“New York City was next on their list of targets,” Mayor Michael Bloomberg said.

The plan fell apart when the Tsarnaev brothers got into a shootout just outside Boston that left Tamerlan Tsarnaev dead, Mr Kelly said.

“We don’t know if we would have been able to stop the terrorists had they arrived here from Boston,” said Mr Bloomberg. “We’re just thankful that we didn’t have to find out that answer.”

Christina DiIorio-Sterling, a spokeswoman for US Attorney Carmen Ortiz in Boston, would not comment on whether authorities plan to add charges based on alleged plan to attack New York.

The Middlesex County district attorney’s office is also building a murder case against the surviving Tsarnaev for the death of Massachusetts Institute of Technology police officer Sean Collier three days after the bombings, office spokeswoman Stephanie Guyotte said.

Investigators and politicians briefed by the FBI have said that the Tsarnaev brothers – ethnic Chechens from Russia who had lived in the US for about a decade – were motivated by anger over the US wars in Iraq and Afghanistan.

Based on the younger man’s interrogation and other evidence, authorities have said it appears so far that the Muslim brothers were radicalised via jihadi material on the internet instead of by any direct contact with terrorist organisations, but they have said it is still an open question.

Dzhokhar was interrogated in his hospital room over a period of 16 hours without being read his constitutional rights.

He immediately stopped talking after a magistrate judge and a representative from the US Attorney’s office entered the room and advised him of his rights to keep quiet and seek a lawyer, according to a US law enforcement official and others briefed on the interrogation.

Tamerlan had come under scrutiny from the FBI, the CIA and Russian intelligence well before the Boston attack.

The CIA had added Tamerlan’s name to a terrorist database 18 months ago, after Russian intelligence flagged him as a possible Muslim radical.

That disclosure is certain to raise questions in Congress over whether the Obama administration missed an opportunity to thwart the Boston attack.

Mr Kelly said there was no evidence New York was still a target. But in a show of force, police cruisers with blinking red lights were lined up in the middle of Times Square yesterday and uniformed officers stood shoulder to shoulder.

In 2010, Times Square was targeted with a car bomb that never went off. Pakistani immigrant Faisal Shahzad had planted a bomb in a sport utility vehicle, but street vendors noticed smoke and it was disabled.

Shahzad was arrested as he tried to leave the country and was sentenced to life in prison.