Less than a week is what it took U.S. law enforcers to track down the suspects of the bomb attacks on the Boston Marathon. For sure, not all questions have still been answered. For instance, if as the FBI has said, there was a request back in 2011 from Russian authorities for information about Tamerlan Tsarnaev and his suspected radical links, and the FBI did carry out some checks on him, including face-to-face interviews, how did it drop the ball on him? More worryingly, did it not fail to read the warning signs? Were Tamerlan, who was killed in last week’s manhunt, and his brother Dzhokhar acting on their own or as part of a group? Did the two men, ethnic Chechens who moved to the U.S. as children, commit this hideous crime for political or ideological reasons? Or are they the product of the same pathological anomie that has driven other shooters and killers in America to perform nihilisitic acts of violence in schools and places of worship from Newtown to Milwaukee? Dzhokhar will no doubt have some of the answers when he recovers enough for officials to speak to him.

The U.S. can take quiet pride in a first class investigation that used the right mix of old fashioned detective work, citizen participation, social media and technology to narrow down a vast and shambolic body of evidence from the scene of the bombing to just the two right suspects. The enormous quantity of blood-stained clothing and other personal effects, and the thousands of video and still images captured by bystanders at the marathon, must have been overwhelming. Yet, a serious, painstaking and methodical sifting, particularly of the images, led investigators to one suspect; the lead for the other came from a man whose legs were blown away in the explosion, but who managed to provide an accurate description of the person who had put a bag with the bomb near his feet. Resisting the pressure there must have been on them to show results, including from a competitive social media doing its own parallel investigations, officials took their time to establish a chronology for the two suspects before going public with their images. The strategically timed release smoked out the two men leading to the manhunt that saw Boston paralysed for a full day last week. The next stage of investigation must now draw in Russia. Putting aside the chill in ties, the presidents of the two countries have already spoken to each other. Among the many lessons from Boston is that international co-operation on fighting terror needs to be taken more seriously, and has to go on, irrespective of the nature of relations between two countries.

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