Report: Russian Officials Warned FBI Alleged Boston Marathon Bomber Was a "Radical"

Russian officials warned the FBI in 2011 that alleged Boston Marathon bomber Tamerlan Tsarnaev may have subscribed to the teachings of "radical Islam," according to the Boston Globe. Tamerlan, who was killed in a shootout with police early Friday morning, is thought to have been the mastermind of the attack that killed three people and wounded about 170. His younger brother, Dzhokhar, who was taken into custody Friday night, remains in serious condition and unable to communicate at a Boston hospital.

While he was living in the U.S., Tamerlan traveled to Russia several times and stayed there for several months in 2012. "Suspicious activities" on his part caught the attention of Russian authorities who were monitoring militant Islamic groups in the Caucasus region in early 2011, the Globe reports. After receiving the warnings, the FBI interviewed the Tsarnaev family but found no ties to terrorism.

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"The FBI had this guy on the radar and somehow he fell off," a senior congressional aide with ties to the Boston Marathon investigation told the Globe.

Meanwhile, sources also tell the Globe that Dzhokhar Tsarnaev went about his routine activities at UMass-Dartmouth in the wake of the bombings, attending classes, going to the gym and sleeping in his dorm room as late as Wednesday night, as police were working to identify who staged the attack.

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"He was just relaxed," according to one of Dzhokhar's classmates, who saw him at a party Wednesday night.