Boston Marathon bombings have to have widely available information , experts say . ` ` Lone wolf '' Nobody in the intelligence community because there 's ` ` no trail , no intelligence '' Pimentel was arrested by New York police in November 2011 and pleaded not guilty to state terrorism charges . Al Qaeda , U.S. right - wing extremists use hard - to - trace bombs , experts say .
Boston Marathon bombings have to have widely available information , experts say . ` ` Lone wolf '' Nobody in the intelligence community because there 's ` ` no trail , no intelligence '' Al Qaeda , U.S. right - wing extremists use hard - to - trace bombs , experts say .