How do you stop a suicide bomber on his way to a target? Until recently, that wasn't an urgent question for scholars in the West. But it is now, and scientists, military strategists and security experts are scrambling, in different directions, to find an answer.

Last year, DARPA, the Pentagon's research arm, convened a panel of experts to study methods to detect suicide bombers before they detonate. Some of the results were interesting, to say the least. One method was called "detection by detonation." The scenario was soldiers at a military checkpoint would fire radiation at each approaching car. The car would pass through safely if nothing explosive was on board. But if the car carried certain materials used by suicide attackers, the tuned radiation would cause their bombs to explode killing anyone unlucky enough to be nearby, but leaving the checkpoint unharmed. A stranger plan involved "distributed biological sensors" - bees, moths, butterflies or rats specially trained to sense bomb vapors in crowded areas.

Not surprisingly, homeland security experts are still looking for other neutralization techniques, ones that don't involve potentially lethal contact or animals that are difficult to control. But there's still a wide division of opinions on the subject. The International Association of Police Chiefs recommended this year that police on the scene simply shoot suspected bombers in the head - "specifically, at the tip of the nose when facing the bomber … or about one inch below the base of the skull from behind." The danger inherent in this approach was illustrated all too plainly last July. The London authorities had an innocent Brazilian man die from their actions, as they enacted their shoot-to-kill policy known as Operation Kratos. Public backlash was harsh and direct, even in the interest of keeping the public transportation tunnels safe.

Non-lethal techniques to disarm bombers are under renewed interest, however. A company called International Security Defense Systems in Dallas offers antiterrorist advice to airlines and airports and employs several former high-ranking members of the Israeli security services.

Chaim Koppel, one of ISDS's trainers, disagrees with the method proposed by the police chiefs' association. He says that it is next to impossible to shoot someone in the head perfectly as they move in random ways. He also claims that many times, a shot to the head could in fact set off a suicide bomb. Koppel and his colleagues instead teach an array of moves based on Krav Maga, the self-defense martial art used by Israeli soldiers, that would disarm but not kill a potential bomber.

The first proposed method:

If you're behind a bomber, the best thing to do is bend down, grab their calves and push up and forward. The bomber will instinctively use his hands to block his fall. If his hands come away from the trigger, grab them and clear the area.

The second method:

Coming head on, you can basically punch the bomber in the face and grab his hands as you push him downwards. It may be violent, but certainly not deadly. And if you get the wrong person, as the London police did, you don't have a corpse on your hands. Merely brush their coat off, say you're sorry and send them on their way.