Investigators released stunning images of Tsarnaev's final moments of freedom, slumbering wounded in a boat in a suburban backyard. They are also stepping up inquiries into a trip to Muslim regions of Russia taken by his accomplice brother, 26-year-old Tamerlan Tsarnaev.
The 19-year-old is "serious but stable," Massachusetts governor Deval Patrick told reporters Saturday. "I think not able to communicate yet."
CNN and other media said he had suffered a throat wound during his cavalcade which ended late Friday after a massive manhunt in which Tamerlan was killed.
The Tsarnaev brothers are the main suspects in the double bomb attack on the Boston marathon which killed three people wounded about 180. A policeman was killed and another was left fighting for his life after gunbattles during the hunt.
Governor Patrick said he hopes the teenager survives. "We have a million questions and those questions need to be answered," he added.
Dzhokhar Tsarnaev was under armed guard at a hospital where some victims of the bombings are also being treated. Counter-terrorism agents trained in interrogating "high-value" detainees were waiting to question him, a law official told AFP.
Prosecutors were also at the Beth Israel Deaconess Hospital in Cambridge, just outside Boston, working out charges.
Media reports say authorities did not read Tsarnaev his normal rights to see a lawyer or stay when he was captured, invoking a special exception for security reasons.
That has left US authorities facing tough decisions over how to handle the investigation and any trial.
Republican Senators John McCain and Lindsey Graham have led calls for the teenager to be declared an "enemy combatant," which would give him the same status as Guantanamo "war on terror" detainees.
Legal rights groups have been quick to insist that he face a criminal trial, even though Tsarnaev would be likely to face a death penalty calls.
The Tsarnaev family are ethnic Chechens who moved to the United States from the former Soviet state of Kyrgyzstan around 2002.
Media reports say Tamerlan Tsarnaev became a fervent Muslim in recent years. Much focus is now being put on his six month trip to the Russian region of Dagestan last year.
US President Barack Obama and Russian President Vladimir Putin agreed during telephone talks Saturday to increase cooperation against international terrorism, the Kremlin and White House said.
The FBI acknowledged on Friday that an unnamed foreign government, reportedly Russia, asked for information about Tamerlan Tsarnaev in 2011. The FBI interviewed the man but said it had found no "derogatory" information.
The men's social media pages appeared to express sympathy with the struggle in Chechnya, which has been ravaged by two wars since 1994 between Russia and separatist rebels.
Dzhokhar Tsarnaev, who became a US citizen last year, was caught after a man named Dave Henneberry saw blood on boat he kept in his backyard in Watertown, in the Boston suburbs. When Henneberry lifted the tarp he saw the wounded teenager curled up inside, police said.
The University of Massachusetts student was surrounded for a showdown that included a final gunbattle before Tsarnaev surrendered to authorities.
Thermal images taken by a police helicopter overhead showed Tsarnaev slumbering in the covered boat. They also showed a robotic arm reaching to lift the cover so cameras could peek inside.
All day Saturday and into Sunday crowds gathered outside Henneberry's home, craning their necks to gaze at his bullet-riddled and blood-smeared 1980s boat.
Neighbor George Pizzuto said that Henneberry was "in shock" and "totally distraught" at the events of Friday night, and is not talking to reporters.
Henneberry has gone into hiding and the boat, his prized possession, is being kept under wraps by police as they collect evidence against Tsarnaev.
Police say the brothers killed one officer and wounded another as they fled, hurling home-made bombs at their hunters.
Tamerlan Tsarnaev died in one gunbattle. His brother was also hit but escaped.
Watertown police chief Edward Deveau said the pair had at least six bombs with them when being chased and that Dzhokhar had driven over his brother as he escaped.
Fifty-eight of the victims from the bomb attack are still in Boston hospitals, with three in critical condition.
COMMENTS (10)
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@Rex Minor: You say that this is a "set up", but then your keyboard ran out of ink!!! Please tell us really did this, since you pretend to know!
Poetic Justice! - This Muslim is being treated in a Jewish hospital in Boston.
his aunt says he turned wahabi : BBC
@Final Solution: But feelings for revenge always arise when fellow brothers and sisters are being murdered by US in any part of world, sorry to say
@G. Din: Using a little commonsense, he could have been captured earlier when he would have been in a far better shape
What if the guy had a suicide jacket on?
How on earth this guy with throat injuies is going to answer the million questions Governor Patick has for him? This is the greatest set up story of all tmes! The chechyan father knows that.
Rex Minor
@Mohaisin Sharif: America didn't invade Chechnya nor used drones to kill people there. Your logic is flawed. Did you know that many Boston Muslims got injured in the attack too
How America handled the capture of the younger brother was conspicuously ham-handed. Imagine a young 19-year old kid, cornered (so conveniently), in a parked boat all covered up, away from the main house and how did the huge police forces of cities and the state respond? Why, they fatigued up, surrounded the boat, brought in the robots and waited for the boy to bleed to incoherence. Using a little commonsense, he could have been captured earlier when he would have been in a far better shape than he is now and the lock-down on metropolitan Boston could have been lifted at least a couple of days earlier . Can one imagine how much all this exercise cost? For some reason, America has this utterly unfounded notion of being all-wise just because it is rich, powerful and prosperous. Had it heeded Russia's input about the elder brother two years earlier this tragedy might have been totally avoided. That was not to be because America knows better than the rest of the world! I daresay even India would have handled the situation with better common-sense.
The root cause behind such attacks is US foreign policy itself, invading countries, killing innocent people with drone attacks, supporting militant groups to destabilize governments and nations, are essential components of American policies!
The upgraded pipe bomb that closed down Boston for two days.. Who will pay the damages? Have Americans gone off the deep end? What's with this "who trained them- who funded them" nonsense. The answer is simple CIA FIA did it .. just don't give up your gunand clips to Israel then you will be as helpless as Pakistan and Somalia