According to journalist and scholar Peter Neumann, a specialist in terrorism and political violence, during the era known as "old terrorism", a pattern of international behavior among terrorist groups was to have a clear hierarchical organization. The author recalls that in the era of "new terrorism", despite having leadership, terrorist groups are becoming increasingly diffuse and difficult to track. Neumann points out two further points in relation to the "old terrorism":
i - that terrorist groups were not motivated solely by religion
ii - that ancient terrorist groups did not aim to kill people - despite the causalities left by some of their attacks. The goal was more of "being seen by people" than of hurting or killing people.