&gt; The 9&#x2F;11 hijackers and the Boston marathon bombers where both flagged yet the attacks still happened because there was simply far to much noise and not enough signal.<p>I&#x27;ve never read that this was a typical &quot;noise&quot;:<p>&quot;NBC News said the Russian intelligence agency FSB cabled the FBI about its concerns in March 2011, warning that Tsarnaev was known to have associated with militant Islamists.&quot;<p><a href="http:&#x2F;&#x2F;www.reuters.com&#x2F;article&#x2F;us-usa-explosions-boston-congress-idUSBREA2P02Q20140326#KLiMs6ZeKSVHdwtB.97" rel="nofollow">http:&#x2F;&#x2F;www.reuters.com&#x2F;article&#x2F;us-usa-explosions-boston-cong...</a>