Boston Bombing Suspect Family: The researchers were looking for a motive for the attacks in Boston Marathon and if others were involved, since Sunday waiting for an opportunity to interview the surviving suspect ethnic Chechen.

Dzhokhar Tsarnaev, 19, was in a Boston hospital seriously injured and unable to speak, after he was captured on Friday night at the end of a great hunt that closed Boston.

His brother, Tamerlane, 26, died in a shootout with police early Friday.

Investigators are trying to determine if other people may have had a role in the detonation of bombs made with a pressure cooker full of ball bearings and nails that exploded in the Boston Marathon on Monday, killing three people and wounding 176.

Tamerlan traveled to Moscow in January 2012 and spent six months in the region, said a police source. But it was not clear what he did while he was there and if I could have had contact with militant Islamist groups in the troubled Caucasus region of southern Russia.

The authorities have yet to charge Dzhokhar, which will be defended by the Federal Public Defender’s Office representing the suspects who can not afford a lawyer.

Sources have suggested that could be charged on Saturday, but officials late in the afternoon in the office of U.S. Attorneys and the Justice Department said no statement was issued before Sunday.

The FBI’s role is also being questioned after the agency said it had interviewed Tamerlane in 2011 after Russian security services expressed concern that Islam was radical. The FBI said it found “terrorist activities” at the time.

But the mother of the suspect, Zubeidat Tsarnaeva, who now lives in Russia, told a Russian TV channel Tamerlan which had been under FBI surveillance for years.

The New York Times, citing unidentified federal officials, authorities had maintained Tamerlan application for U.S. citizenship by 2,011 FBI interview.

Records show that Tamerlane was arrested when police were called to a report of domestic violence in 2009.

The FBI believes that the older brother was the leader of the pair, although investigators were checking people who had contact with the two brothers to see if anyone else was involved, said a source from the application of U.S. law . high level.

Early indications are that the brothers acted alone, Watertown Police Chief Edward Deveau told CNN on Saturday. “From what I know now, these two acted together alone,” he said.

However, the bombing caused contact between the U.S. and Russia, and the Kremlin said on Saturday the presidents of both countries agreed by phone to increase cooperation in the fight against terrorism.

Tsarni Ruslan, who said he was an uncle of the brothers told CNN Saturday that first noticed a change in the religious opinions of Tamerlane in 2009. He suggested his nephew radicalization occurred while in the United States “on the streets of Cambridge (Massachusetts).”

More details of the lives of the brothers apparently contradictory continued to emerge Saturday.

Tamerlan married Katherine Russell, whose family lives in an upper middle class neighborhood in North Kingstown, Rhode Island. His father is licensed as emergency medical. The couple had a small child.

A statement on the front door of the family said: “Our daughter has lost her husband today, the father of her child can not begin to understand how this horrible tragedy occurred.”

“STILL CAN NOT SPEAK ‘

Dzhokhar, a student at the University of Massachusetts Dartmouth, was shot in the throat and could not speak because of lesions on the tongue, said a source close to the investigation. It was unclear whether he would be able to speak.

We have a million questions and these questions must be answered,” Massachusetts Gov. Deval Patrick told reporters on Saturday.

Dzhokhar had been hidden in a boat parked in the backyard of a house in the suburb of Watertown and was captured after a resident saw blood on the boat and called the police. He was being treated at Beth Israel Deaconess Medical Center in Boston.

After combing through a lot of pictures and video from the site, in the minutes before the attack Boston Marathon, the FBI released a video of the two men on Thursday and asked the public for help in identifying them.

Just hours later, the events began to unfold with the shooting death of Police Sean Collier, 26 years in the Massachusetts Institute of Technology campus and finally a mass shooting in Watertown, where police say the brothers dropped bombs on the officers. Tamerlan suffered fatal injuries while Dzhokhar escaped on foot.

The family emigrated to the United States a decade ago. The brothers spent their early years in a small Chechen community in the Central Asian country of Kyrgyzstan, a predominantly Muslim country of 5.5 million. The family moved in 2001 to Dagestan, a province in southern Russia which is located in the heart of the violent Islamist insurgency and where his parents live now.

(Additional reporting by Martinne Geller, Tabassum Zakaria, Mark Hosenball, John Shiffman, Jim Bourg, Svea Herbst-Bayliss, Daniel Lovering, Ben Berkowitz, Barbara Goldberg, Ed Krudy and Olga Dzyubenko; Written by Edward Krudy, Editing by Doina Chiacu, Vicki Allen, Peter Cooney and Xavier Briand)