If you remain suspicious, trust your instincts. Off-duty officers generally work armed and are aware of security procedures. Make sure the dispatcher understands the emergency nature of the call and the need for a law enforcement response without sirens. Assign an usher to inconspicuously monitor the location of the individual. If you choose to admit the person to the sanctuary pending assistance (e.g., arrival of police) invite the person to sit on an aisle seat. Excuse yourself and initiate your procedures, perhaps by using a pre-determined code-word with your colleagues. Evasive or unusual answers may trigger your emergency procedures. If you choose to investigate, greet the person in a friendly fashion, asking "Can I be of assistance?" or "Welcome, is this your first time here?" (Your membership committee will appreciate this gesture). This is a decision only you can make in light of the circumstances, your personal comfort level and safety considerations. While, again, no one factor is a certain indicator of a problem, once a problem is identified, ushers and security personnel have three options: do nothing, investigate and decide whether to take emergency steps, or immediately take emergency steps. Some also anointed themselves with scented oil, which may be obvious to someone in their vicinity.
(The majority of suicide bombers there have been males, 18 - 27).
For example, Israelis have become aware that some suicide bombers shaved off beards prior to committing their acts, thus leaving untanned skin and unusual facial tan lines. The most important thing is to be observant. Security people should be told, where possible, to observe people as they exit their cars by watching how they adjust clothing and how they approach the building, they can look for signs that a person might be carrying a weapon, etc. Lack of understanding of basic religious procedure/norms appropriate to the institution such as a synagogue.Carrying packages (see below regarding food donations).Suicide bombers have been known to repeatedly pat themselves to verify that the bomb vest or belt is still attached. Projected angles under clothing may also be indicative of a firearm, e.g., at the waist or the ankle.
Pay attention to a person constantly adjusting waistbands, ankles, or other clothing.
Suspicious people may often be identified by their behavior.