BOSTON -- New details emerged Tuesday from U.S. officials and family members about how the two Boston Marathon bombing suspects may have been swayed by a radical, anti-American strain of Islam.
A U.S. senator said they had been radicalized by sources on the web, not through direct contact with terror groups.
The condition of the younger brother, Dzhokhar Tsarnaev, was upgraded from serious to fair as investigators continued building their case against the 19-year-old university student.
He could face the death penalty after being charged Monday with joining forces with his brother, now dead, in setting off the shrapnel-packed pressure-cooker bombs that killed three people.
More than 260 people were injured by the bomb blasts last week. About 50 were still hospitalized.
In Washington, Republican Sen. Richard Burr said after the Senate intelligence committee was briefed by federal law enforcement officials there is "no question" older brother Tamerlan Tsarnaev was "the dominant force" behind the attacks, and the brothers had apparently been radicalized by material on the Internet rather than by contact with militant groups overseas.
Authorities believe neither brother, both Russian-born ethnic Chechens, had links to terror groups. However, two U.S. officials said Tuesday Tamerlan Tsarnaev, 26 -- who died last week in a gun battle -- frequently looked at extremist websites, including Inspire magazine, an English-language online publication produced by al-Qaida's Yemen affiliate. The magazine has endorsed lone-wolf terror attacks.
Both officials spoke on condition of anonymity because they were not authorized to discuss the investigation publicly.
Family members reached in the U.S. and abroad by The Associated Press said Tamerlan was steered toward a strict strain of Islam under the influence of a Muslim convert known to the Tsarnaev family only as Misha.
After befriending Misha, Tamerlan gave up boxing, stopped studying music and began opposing the wars in Afghanistan and Iraq, according to family members, who said he turned to websites and literature claiming that the CIA was behind the Sept. 11, 2001 attacks.
"Somehow, he just took his brain," said Tamerlan's uncle, Ruslan Tsarni of Maryland, who recalled conversations with Tamerlan's worried father about Misha's influence.
"You could always hear his younger brother and sisters say, 'Tamerlan said this,' and 'Tamerlan said that.' Dzhokhar loved him. He would do whatever Tamerlan would say," recalled Elmirza Khozhugov, the ex-husband of Tamerlan's sister. He spoke by telephone from his home in Almaty, Kazakhstan.
The brothers, who came to the U.S. from Russia a decade ago, were raised in a home that followed Sunni Islam, the religion's largest sect, but were not regulars at the mosque and rarely discussed religion, Khozhugov said.
Then, in 2008 or 2009, Tamerlan met Misha, a heavyset bald man with a reddish beard. Khozhugov didn't know where they met but believed they attended a Boston-area mosque together.
Hoping to learn more about the motives, U.S. investigators travelled to southern Russia on Tuesday to speak to the parents of the two suspects, a U.S. Embassy official said.
The parents live in Dagestan, a predominantly Muslim province in Russia's Caucasus, where Islamic militants have waged an insurgency against Russian security forces for years.
A lawyer for the family, Zaurbek Sadakhanov, said the parents had just seen pictures of the mutilated body of their elder son and were not up to speaking with anyone.
In Washington, members of the Senate Intelligence Committee were briefed by the FBI and other law enforcement officials at a closed-door session Tuesday evening.
Afterward, Republican Sen. Marco Rubio described the two brothers as "a couple of individuals who become radicalized using Internet sources."
-- The Associated Press