Tamerlan Tsarnaev had been on the FBI's radar for two years before the Boston Marathon bombings he's suspected of carrying out. A U.S. law enforcement official told Reuters Saturday that Russia had asked the FBI to investigate Tsarnaev and, after interviewing him and checking out his travel records, internet history and personal associations, they "did not find any terrorism activity." Friday, the suspect's mother told Russia Today that the FBI had previously reached out to her about her son's extremist views.
