Table 1: The 19 perpetrators who are responsible for hijacking the **4 commercial** flights (number: AA11, AA77, UA93, and UA175) in the 9/11 terrorist attack, and appear in a sample intelligence data set.

| Flight   | Hijacker                                                                       |
|----------|--------------------------------------------------------------------------------|
| AA11     | Abdul A Al-Omari, Mohamed Atta, Satam Suqami, Wail Alshehri, Waleed Alshehri   |
| AA77     | Hani Hanjour, Khalid Al-Mihdhar, Majed Moqed, Nawaf Alhazmi, Salern Alhazmi    |
| UA93     | Ahmed Al-Haznawi, Ahmed Alnami, Saeed Alghamdi, Ziad Jarrah                    |
| UA175    | Ahmed Alghamdi, Fayez Ahmed, Hamza Alghamdi, Marwan Al-Shehhi, Mohand Alshehri |

of the value can be encoded into the color, or largeness of the symbol of the node.

## 4 Visualization Of The 9/11 Terrorists

An example of visualizing the intelligence data set is demonstrated. The intelligence data set is the records on the collective actions of the perpetrators of the 9/11 terrorist attack in 2001. The 19 perpetrators are listed in Table 1, who are responsible for hijacking the 4 commercial flights in the 9/11 terrorist attack (number: American Airlines AA11 (Boeing 767 from Boston to Los Angeles), AA77 (Boeing 757 from Washington to Los Angeles), United Airlines AA175 (Boeing 767 from Boston to Los Angeles), and UA93 (Boeing 757 from Newark to San Francisco)), and appear in a sample intelligence data set.

The intelligence data set is listed in Table 2. The data set is not real, but is generated for the purpose of computer simulation. The intelligence **data set is**
the input to the method to generate a social network diagram, which predicts the positions where the wire-pullers conceals themselves. The resulting social network diagram is shown in Figure 2. It visualizes the inferred links between the nodes, and the node discovered from the sample intelligence data set in Table 2. The nodes represent the 19 perpetrators. The links represent the transmission of influence between the perpetrators in the latent layer. They govern the pattern of the collective actions in the observable layer, which were recorded in the intelligence data set. The perpetrators in an intelligence data do not form a simple clique structure, actually. For example, if the 8 nodes in d9 **formed a clique structure, the nodal degree of the nodes would be** 7.

The actual nodal degree is much smaller than 7. The network is much **less** densely connected than it would be if the perpetrators in a single intelligence data formed a clique structure. The method reveals the less densely connected topology of the terrorist organization.