Indications of an attack, often referred to as pre-incident indicators (PIIs), are wide-ranging and are based predominantly on unusual occurrences. The maxim 'the absence of the normal and the presence of the abnormal' is a neat definition of PIIs. Unusual activity involving people is often a primary indicator: this could include an unusual gathering or dispute to create a distraction or may just as easily take the form of an individual loitering or reconnoitring a possible target. A normally busy road could be made unusually quiet deliberately, to keep unintended targets from straying into the killing area or to allow a suicide truck bomber unimpeded access to a target. People who seem unduly observant and focused, where others would normally seem distracted or carefree, can also provide an early warning. Even something as normal as speaking on a mobile phone could be deemed suspicious in certain circumstances.
Indications of an attack
Baggy or excessive clothing is often worn by suicide bombers: in hot countries this can seem incongruous. Excessive sweating, or wearing clothes inappropriate to the size of the individual or the prevailing climatic conditions, might also arouse suspicion. Disguises have also been worn to make individuals look obese, or pregnant in the case of women. Both these disguises can in themselves result in excessive heat and associated sweating independent of that induced by nervousness. It should be noted, however, that both obesity and pregnancy can naturally result in excessive sweating.
Up to the point of explosion, the bomber may be observed praying fervently, giving the appearance of someone whispering or muttering. He or she may also smell of flower water (most likely rose water) as Islamic suicide attackers are sometimes instructed to spray perfume on themselves, their weapons, or their possessions in order to prepare themselves to enter paradise.
If the device is hand-carried, the attacker will usually maintain a strong grip on the bag, keeping it close to their body and squeezing or even stroking it. Recently backpacks have been the container of choice. A string or wire, wrapped around the hand or held in it, protruding from an oversized jacket or from within a bag, may be indicative of a pull initiator. Such initiators minimise the possibility of premature explosions that commonly occur with toggle switch or electronic time initiators.
There are also a number of indicators for a potential suicide car attack. A vehicle low on its axles could indicate excessive weight caused by a large quantity of explosives being present. An unusually fast- or slow-moving vehicle could be an indication of a timer being present, and signs of distress from the car's occupants could suggest that it has been hijacked. Also, mismatched front and rear number plates, dark stickers in the driver's side window - to limit visibility into the vehicle - and unusual vehicle content such as barrels could all suggest a vehicle laden with explosives.
Essentially, a single isolated unusual occurrence is unlikely to be a definite indication of a pending terrorist attack, but a combination of abnormal occurrences could well be a sign that an attack is imminent.
Countering suicide bombing at the tactical level
If attempts to prevent suicide attacks fail at the strategic and operational levels, it is up to the tactical responders, including the police and explosive ordnance disposal operators as well as the target population itself, to form the last line of defence. It is in this area that suicide terrorism presents the greatest threat to the individual.
The most effective way of preventing suicide attacks from occurring at the tactical level is through the use of adequate physical security measures.
Establishments with alert and vigilant security staff, educated and security-aware employees, and other physical measures such as closed-circuit television, access control and stand-off security barriers are far less likely to be attacked than soft targets. It is also important to conduct regular security, vulnerability and risk assessments so that effective contingency plans may be drawn up to detail any necessary attack-mitigating emergency procedures. These procedures, including those for suicide attacks, must then be exercised regularly.
If suicide attacks continue despite the introduction of such measures, the security forces provide the last line of defence. From a tactical perspective, the first priority must be to detect the suicide bomber. Even without good intelligence, this can still be achieved through the maintenance of vigilance and observation by identifying the physical 'indicators' mentioned previously.
Detection success can also be significantly assisted through the use of strategically placed electronic detection equipment. Most buildings of national importance, for example, have some form of security and many have metal detection or x-ray facilities. It is also possible to use long-range metal detectors to assist the identification of possible suicide bombers, as most suicide devices contain a large metal content so that fragmentation will enhance the destructive effect. Similarly, stand-off explosives detectors - and, in the case of radio-controlled devices, electronic countermeasures (ECM) equipment - can also be used to detect a suicide bomber. Once detected the aim is to detain the perpetrator and to neutralise the device.
Neutralisation of the device
Before the device can be rendered safe the bomber has to be detained and isolated as quickly and efficiently as possible. This is the most potentially hazardous phase of the operation. One method of detaining a suicide bomber is by means of a speedy 'hard arrest', which relies on the element of surprise coupled with a substantial element of luck. The perpetrator must be immobilised and held on the ground, lying face up with his or her arms held away from the body and both legs held securely.
Alternatively, he or she could be physically secured to a solid object using handcuffs or plasticuffs. The advantage of the hard arrest method is that the suspect perpetrator remains alive and can be brought to justice, or be processed and released if it is a case of mistaken identification and the individual is not carrying a device. Conversely, the obvious disadvantage is that if a device is present, there is a high probability that the attacker will be able to detonate it before being sufficiently immobilised.
Another option in preventing a suicide attack might be to 'neutralise' the bomber using lethal force. A single shot to the head1 from a high-velocity weapon is the method most likely to result in the necessary immediate and total disablement of the attacker and, as it can be achieved from a standoff position, it presents minimal risk to security force personnel.
This method presents two obvious disadvantages, however. Firstly there is a chance that the device could be fitted with a 'dead man switch' which, if released, would detonate the device; and secondly, since suicide bombers conceal their devices, there is always the possibility of killing an 'innocent' who may be considered as acting in a suspicious manner but is not in fact a suicide attacker at all. The shooting option should therefore only be used when a device can be positively identified or on the authority of a higher command.
Both means of detaining a suicide bomber require an immediate EOD (explosive ordnance disposal) response, due to the fact that there could be a backup timer or radio-controlled firing mechanism. It therefore stands to reason that all arrests should be conducted under active ECM cover and that either an EOD operator or team should always be in intimate support of the security forces during the arrest, depending on the tactical situation. In all instances thorough questioning is crucial and the EOD operator must gather as much background intelligence as possible before, during and after the attack, including technical intelligence and information on the terrorist group, especially its modus operandi and history of the devices it has used previously.
In line with existing improvised explosive device disposal philosophy, disablement through disruption should be the preferred means of neutralisation of a device, but a high-explosive donor charge could also be an option under certain conditions. Hand tools to facilitate advanced manual techniques and x-ray equipment should also be available, especially if the incident is deemed 'Category A' and the only alternative is to neutralise the device manually. When using x-ray equipment, however, particular attention should be paid to the possibility of x-ray-sensitive switches.2 In the case of manual neutralisation, both the suicide bomber and the device should be thoroughly stabilised before any techniques are undertaken.
In all circumstances the preservation of life is paramount and must always take precedence over property and forensic evidence, although the aim should be to preserve both wherever possible. Operators should spend the minimum time at risk, use remote means where possible, employ a 'single man risk' philosophy and make full use of relevant soak times and adequate protective equipment. In addition, operators should always endeavour to restore the situation to normal as soon as possible.
Chris Williams is an expert in explosive ordnance disposal
1 A shot to the head will incapacitate the terrorist more quickly than a body shot and is less likely to initiate the device unintentionally.
2 Middle Eastern terrorists have used x-ray-sensitive firing switches in the past to defeat EOD operators.