And while in the Islamist terrorism cases firearms and explosives figured into around a third of the cases , more than half the cases of non-Islamist terrorism involved firearms or explosives . 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 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 .