Bomb hidden in body in Saudi attack "invisible" to normal detection

Published 4 October 2009

A terrorist in Saudi Arabia tried to kill the Saudi antiterror chief by carrying explosives inside his body; experts say there are “tremendous implications for airport security with the potential of making it even more complicated to get on to your plane”

We wrote two weeks ago about a terrorist using explosives concealed inside his body who blew himself up on receipt of a mobile phone signal (9 September 2009 HSNW). The terrorist passed through several checks undetected. The attack has security experts very worried that this method is likely to become a real threat.

The intention was to kill a Saudi prince, who happened to be the chief of antiterrorism operations in Saudi Arabia in a complex plot involving the terrorist gaining access to the target by pretending to defect.

Paul Wallis writes that it nearly worked, too. The terrorist met the prince, and they phoned another party, believed to be the terrorist’s boss, in an attempt to get him to defect. That was when the bomb went off. The bomb is believed to have been triggered by a mobile phone signal, evidently based on the fact that the other phone call confirmed the target was in range.

The prince was slightly injured, but the possibilities of this method have security experts extremely concerned.

The BBC reports:

Peter Neuman of Kings College London says the case will be studied intensively, and that there are “tremendous implications for airport security with the potential of making it even more complicated to get on to your plane.”

If it really is true that the metal detectors couldn’t detect this person’s hidden explosive device, that would mean that the metal detectors as they currently exist in airports are pretty much useless,” he said.

Looking at this logically there are a few obvious points:

  • The bomb was C4 plastic explosive or a relative.
  • The detonator and receiver had to be of materials which don’t produce much of a response from a metal detector. The receiver could be germanium, which is the receiver in crystal sets. It’s an unusual material which receives energy from radio waves, which is how it powers crystal sets.
  • The signal needs to be to a preset receiver. That means it’s a unique signature on the phone calls.

Possible detection countermeasures

  1. X rays calibrated for soft materials. Not easy, but it’s a readily available detection method.
  2. MRI scans. Expensive, but possible. MRI can detect and analyze non metallic materials.
  3. Thermal profiling may be able to be calibrated to receive anomalous signals. All materials have distinct thermal signatures. Probably the cheapest, and certainly the most effective if it can be done on a large scale.

Operational countermeasures

  1. If phone services can read anomalous signals to unspecified locations, they can locate the sender and the receiver, at least in theory. A GPS reference would be easy enough to create.
  2. Sensitive areas could be subjected to jamming measures.
  3. Airports could simply require phones to be turned off, or confiscated, to reduce local phone traffic within the security zones.

Wallis writes that it will be interesting to see how this pans out. It is a difficult operational problem, but the theory part of it does have some basis for hope this new method can be shut down pretty effectively.

The likely result of this attack will be to force a new wave of countermeasures around the world. “Let’s hope they get it right, because Mr. Neuman’s comments are a good description of the situation if they don’t,” Wallis concludes.