BOSTON -- Dzhokhar Tsarnaev, the surviving suspect in the Boston Marathon bombings, is awake in a Boston hospital and responding in writing to questions, a law enforcement official said Sunday.
Investigators who have been waiting to interrogate Tsarnaev are looking into the possibility that his neck wound was self inflicted, a federal law enforcement official said.
The official, who has been briefed on the matter but is not authorized to comment publicly, said that suspicions of a suicide attempt before he was captured center on the small appearance of the entry wound and larger exit wound area
A law enforcement official confirmed that the suspect was awake Sunday evening. Earlier, Boston Police Commissioner Ed Davis told reportersthat Tsarnaev was still "not in any condition to be interrogated.'' He said the suspect's condition has only stabilized in "the last few hours.''
Though the suspect's condition was listed as serious, Davis said "serious and critical are interchangeable.''
Separately, the official said it will likely take "some time'' before agents are able to review information held by Russian authorities that prompted the Russian government to ask the FBI in 2011 to review the activities of Tamerlan Tsarnaev, the older brother who died in a gunfight with police in Watertown.
The U.S. attorney's office, meanwhile, said no charges would be filed Sunday.
Davis said on CBS' Face the Nation that police believe Tsarnaev and his brother, Tamerlan Tsarnaev, 26, "were going to attack other individuals."
Dzhokhar Tsarnaev, who was captured Friday after a dramatic manhunt that paralyzed Boston and its suburbs, is under heavy guard in a Boston hospital.
The brothers' uncle, Ruslan Tsarni, told the Associated Press that Dzhokhar Tsarnaev was "used" by his older brother to carry out the bombing. "He's not been understanding anything," Tsarni said. "He's a 19-year-old boy."
The Tsarnaev family are ethnic Chechens who came to the United States from Kyrgyzstan and Dagestan.
Tsarni also told the AP that his relationship with his nephews deteriorated several years ago when Tamerlan Tsarnaev "started carrying all this nonsense associated with religion, with Islamic religion" and began using words such as "jihad" without really understanding their meaning.
Reps. Peter King and Michael McCaul, Republican members of the House Homeland Security Committee, want federal officials to explain why Tamerlan Tsarnaev was released by the FBI after it questioned him in 2011 at the request of Russia's government.
Also drawing scrutiny: Tamerlan Tsarnaev's trip to Russia last year and whether he returned with more radical political and religious views.
In Makhachkala, Russia, the Tsarnaev brothers' parents insisted that Tamerlan visited Dagestan and Chechnya last year to see relatives and had nothing to do with militants.
His father said his son stayed with him in Makhachkala, the capital of Dagestan, where the family lived briefly before moving to the U.S. a decade ago. The father had only recently returned.
"He was here, with me in Makhachkala," Anzor Tsarnaev told the Associated Press in a telephone interview. "He slept until 3 p.m., and you know, I would ask him: 'Have you come here to sleep?' He used to go visiting, here and there. He would go to eat somewhere. Then he would come back and go to bed."
On Sunday, the Caucasus Emirate, which Russia and the U.S. consider a terrorist organization, denied involvement in the Boston attack.
A woman who works in a small shop opposite Tsarnaev's apartment building said she only saw his son during the course of one month last summer. She described him as a dandy.
"He dressed in a very refined way," Madina Abdullaeva said. "His boots were the same color as his clothes. They were summer boots, light, with little holes punched in the leather."
Rep. Mike Rogers, R-Mich., chairman of the House Intelligence Committee, said Sunday that information about Tamerlan Tsarnaev's travel to Russia last year indicated that he used an alias while traveling there.
Rogers said on NBC's Meet the Press that while the elder suspect's six-month trip would be the subject of review, he did not believe the FBI had failed to detect suspicious behavior when the Russian government asked the bureau to review Tsarnaev's activities before his 2012 Russian trip.
"I don't think they missed anything,'' he said.
Anwar Kazmi, a board member of Islamic Society of Boston, said Tamerlan Tsarnaev interrupted a sermon about three months ago when the imam compared Martin Luther King Jr. to the prophet Mohammed. Kazmi said Tsarnaev objected to the comparison.
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