BOSTON -- Boston Marathon bombing suspect Dzhokhar Tsarnaev lay hospitalized in serious condition under heavy guard Saturday -- apparently in no shape to be interrogated -- as investigators tried to establish the motive for the deadly attack and the scope of the plot.
People across the Boston area breathed easier the morning after Tsarnaev, 19, was pulled, wounded and bloody, from a tarp-covered boat in a Watertown backyard. The capture came at the end of a tense day that began with his 26-year-old brother, Tamerlan, dying in a gunbattle with police.
There was no word on when Tsarnaev will be charged and what those charges will be. The twin bombings killed three people and wounded more than 180. Also killed was an MIT police officer, who was shot to death while the brothers were trying to evade capture.
The most serious charge available to federal prosecutors would be the use of a weapon of mass destruction to kill people, which carries a potential death sentence. Massachusetts does not have the death penalty.
President Obama said there are many unanswered questions about the bombing, including if the Tsarnaev brothers -- ethnic Chechens from southern Russia who had been in the United States for about a decade and lived in the Boston area -- had help from others. The president urged people not to rush judgment about their motivations.
U.S. officials said an elite interrogation team will question the Massachusetts college student without reading him his Miranda rights, something that is allowed on a limited basis when the public might be in immediate danger, such as instances in which bombs are planted and ready to go off.
The American Civil Liberties Union expressed concern about that possibility. Executive Director Anthony Romero said the legal exception applies only when there is a continued threat to public safety and is "not an open-ended exception" to the Miranda rule, which guarantees the right to remain silent and the right to an attorney.
The federal Public Defender's Office in Massachusetts said it has agreed to represent Tsarnaev after he is charged. Miriam Conrad, public defender for Massachusetts, said Tsarnaev should have a lawyer appointed as soon as possible because there are "serious issues regarding possible interrogation."
Massachusetts Gov. Deval Patrick said Saturday afternoon that Tsarnaev is in serious but stable condition and probably is unable to communicate. Tsarnaev is at Boston's Beth Israel Deaconess Medical Center, where 11 victims of the bombing are still being treated.
"I -- and I think all of the law enforcement officials -- are hoping, for a host of reasons, the suspect survives," the governor said after a ceremony at Fenway Park to honor the dead and wounded from the attack. "We have a million questions, and those questions need to be answered."
Investigators have not offered a motive for the Boston attack, but in interviews with officials and those who knew the Tsarnaevs, a picture has emerged of the older brother as someone embittered toward the United States, increasingly vehement in his Muslim faith and influential over his younger brother.
The Russian FSB intelligence service told the FBI in 2011 about information that Tamerlan Tsarnaev was a follower of radical Islam, two law enforcement officials said Saturday.
According to an FBI news release, a foreign government said that Tamerlan Tsarnaev appeared to be a strong believer and that he had changed drastically since 2010 as he prepared to leave the United States for travel to the Russian region to join unspecified underground groups.
The FBI did not name the foreign government, but the two officials said it was Russia.
The FBI said that, in response, it interviewed Tamerlan Tsarnaev and relatives, and did not find any domestic or foreign terrorism activity. The bureau said it looked into such things as his telephone and online activity, his travels and his associations with others.
An uncle of the Tsarnaev brothers said he had a falling-out with Tamerlan over the man's increased commitment to Islam.