Boston attacks lead to intelligence review THE US government is reviewing the handling and sharing of intelligence that occurred before the Boston Marathon attacks. Tamerlan Tsarnaev, 26 and his younger brother Dzhokhar are accused of carrying out the April 15 bombings at the Boston Marathon, which killed three and wounded more than 264 at one of the world's premier sporting events. The Inspectors General of the Intelligence Community says the review will examine the information available to the US government before the bombings and the information sharing protocols and procedures followed between and among the intelligence and law enforcement agencies. The Central Intelligence Agency, the Department of Justice and the Department of Homeland Security are also taking part in the review. US politicians and commentators have questioned why Tamerlan Tsarnaev - the accused mastermind of the attack, who was killed in a police shootout - was not seen as a threat in the years before the bombing. The Federal Bureau of Investigation (FBI) questioned Tsarnaev, an ethnic Chechen, at Russia's request in 2011. The following year Tsarnaev, who appears to have posted radical Islamist videos on social media, travelled to the volatile North Caucasus region of Russia, home to several fierce Islamist and separatist groups for six months. On Tuesday, Obama defended the FBI and said US authorities had done the best they could in the face of threats that include what he described as "self-radicalised individuals." Based on what I've seen so far, the FBI performed its duties, the Department of Homeland Security did what it is was supposed to be doing. But this is hard stuff," Obama told a news conference on Tuesday. He added that Russia had been very co-operative in the post-bombing probe but acknowledged lingering suspicions between the intelligence and law enforcement agencies of the two former Cold War foes. "You know, old habits die hard," Obama said. Tamerlan Tsarnaev died in a shootout with police as he tried to flee the Boston area three days after the bombing. His younger brother was wounded and captured, and now faces terror charges carrying a possible death sentence.