It's worse than that. Not only did they ignore warnings, they got sucked into the Muslim Brotherhood device of distraction, dawah and dissembling, "Muslim Outreach." Read my column on this very thing: The Fatal Fallacy of Muslim Outreach - American Thinker
"FBI ignored warnings about Boston bombers’ radical mosque" By Charles Jacobs and Ilya Feoktistov The Daily Caller | July 25, 2013
Federal Bureau of Investigation officials ignored warnings about the radical origins and nature of the mosque frequented by the Tsarnaev brothers for years before this April’s deadly Boston Marathon bombings.
Outgoing FBI Director Robert Mueller has also said that although the FBI visited the mosque in the past — as part of its “outreach” to the Muslim community — he was unaware of the Islamist leanings of the Islamic Society of Boston (ISB), which runs the Boston bombers’ house of worship.
But the FBI was warned nearly four years prior to the bombings that the ISB was a nest of Islamic radicalism.
On May 1, 2009 our organization, Americans for Peace and Tolerance (APT), briefed representatives of the Boston FBI office on the ISB mosques’ affiliation with Islamic extremism. Nevertheless, the FBI continues to claim it was surprised by the background of the ISB.
In a June appearance before the House Judiciary Committee, Mueller described how it took four days after the Boston Marathon bombings for his agency to canvass the Tsarnaev brothers’ controversial mosque.
After tough questioning by the highly perturbed Texas Republican Rep. Louie Gohmert, Mueller confessed that he had absolutely no idea the Tsarnaevs’ mosque was founded by Abdulrahman Alamoudi, who was convicted in 2004 of plotting with Libyan dictator Muammar Gaddafi to assassinate Saudi Crown Prince Abdullah Bin Abdul-Aziz.
But a review of the PowerPoint slides we used in our 2009 presentation confirms that we did alert FBI agents in Boston about Alamoudi and much more.
Legitimate warnings such as those we provided about ISB get ignored, however, because the Obama administration in 2011 instructed national security agencies to remove language “offensive to Muslims” from all of its reports and considerations. Agents may no longer refer to Islamic religious convictions as motives for terrorist acts. Even when suspects announce that they murdered Americans “for Allah,” the FBI can’t use that as an indication of what may be coming next.