Recent terror alert raises concern about Al Qaeda , authors say . Their study shows domestic terrorism often comes from non - Islamist groups . Non - Islamist terrorists have been more likely to seek unconventional means , they say . Authors : In U.S. , Islamist terrorism no more deadly than other terrorism since then .
Recent terror alert renews concern about al Qaeda , authors say . Their study shows domestic terrorism often comes from non-Islamist sources . Non-Islamist terrorists have been more likely to seek unconventional weapons , they say . Authors : In U.S. , Islamist terrorism no more deadly than other forms since 9/11 .