On ABC this morning, Mike Rogers, a Republican congressman from Michigan and chairman of the House intelligence committee, explained that the FBI is still investigating the involvement of other individuals in the deadly Boston Marathon bombing, and considers a certain number of people in the U.S. to be ”persons of interest.” He would not provide a specific number.

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“We still have persons of interest that we’re working to find and identify and have conversations with,” Rogers said. He offered one explanation of how these “persons of interest” might have been involved, saying that in every instance of violent jihad, “there was outside affirmation of their intent to commit an act of jihad. I believe that happened in the United States.”