Even if every airport in the United States scanned every bag loaded onto every airplane for explosives, and every passenger went under the metal-detector, a bomb could still get onto a passenger jet, experts say. The Federal Aviation Authority's next generation of holographic body imaging scanners can be trumped too. Welcome to the world of the "terror mule."
Criminal groups running drugs and diamonds into the United States have for years smuggled contraband by stuffing it into condoms and having a "mule" swallow the load, or by having it implanted surgically or rectally. The same technique can be used to smuggle plastic explosives like Semtex past security at an airport.

Triggering mechanisms could be made with few metal components to evade detections, or could be assembled from common electronic gadgets such as PDAs, cell phones, laptops or personal stereos. Terrorists could even rig up a wireless detonator that could be triggered from the ground.

"It absolutely can be done and very easily, and there's no reason to believe that wouldn't be possible," said Dr. Harvey Kushner, chairman of the criminal justice department at Long Island University. Kushner is also a terrorism expert who testified at the criminal and civil cases that followed the bombings of the U.S. embassies in Africa, the first World Trade Center attack, and the destruction of Pan Am flight 103.

"Quite frankly, that kind of experimentation has been taking place. We know that they have been testing strapped-on explosives on animals in the Middle East for years and it's not a magical leap to try inserting it into the rectum," he said.

Dr. Kushner is the author of Terrorism in America and The Future of Terrorism: Violence in the New Millennium and the upcoming Concise Encyclopedia of Extremism and Terrorism.

Terrorists have already used mocked pregnancy prosthetics to slip bombs aboard planes, but no one has tried the mule approach yet, according to Harvey "Jack" McGeorge, a former Marine Corps bomb disposal specialist and a former Secret Service security specialist.

McGeorge is now president of the Public Safety Group, a consultancy based in Woodbridge, Virginia, which studies chemical and biological warfare and terrorism.

"I agree that that's doable. I see no bar to this," McGeorge said. However, unlike Kushner, McGeorge said he hadn't heard of animal testing.

McGeorge estimated that a suicide bomber could smuggle at least a single bar of C-4, a U.S.-made plastic explosive, measuring about 1.5 inches in diameter and 7 to 8 inches long. That would yield something in comparison to a pound of dynamite, he said. "I would say, you could smuggle about three pounds vaginally and a pound anally," McGeorge said.

Another specialist said the total load could be well over five pounds if more explosives were smuggled in the stomach. Kushner noted that Pan Am Flight 103 was brought down with under four pounds of Semtex.

The bomber could simplify detonation with a self-contained timer, instead of relying on a wireless trigger or other mechanisms, McGeorge added. Removing the explosives in the bathroom could optimize strategic placement.

"I have seen no intelligence reporting on the prospect of rectally implanted explosive charges being carried aboard aircraft by individuals willing to be a living bomb," said one national intelligence researcher, who asked to remain anonymous. "(But) the scenario is plausible. The notion is straightforward, and the events of 9-11 have shown us that we must give weight to suicidal attacks ... against aircraft or other targets."

Richard Horowitz, an attorney, private investigator, and captain in the Israel Defense Forces who consults on terrorism issues, said: "It's not appropriate for an analyst of terrorism to consider anything absurd that is technically very feasible, and I would say yes, this is. I have not heard this scenario discussed, but Tom Clancy wrote up a plot that involved crashing a jet into a building, and the federal authorities classified it as a low probability."

By smuggling explosives inside one's body, a suicide bomber would likely foil all of the current airport scanning technologies, as well as many future ones.

The FAA is purchasing five Secure1000 holographic imaging scanners from Rapiscan for testing at its William J. Hughes Technical Center, said Holly Baker, a spokesperson for the agency. The Rapiscan uses X-rays, but the company itself conceded that its weak rays can't look into tissue, only under clothing.

Other scanning technologies using magnetism, thermal imaging, and other forms of radiation detection also have difficulty getting below the skin. Most of the technology was developed in the pre-9-11 era when hijackers used guns, and there was some hope of them living through the hijacking.

One surveillance device that might overcome the terror mule is being developed in the Netherlands: MMC International's Conpass Digital Body Scanner, which is being used at the Schiphol Airport in Amsterdam.

The scanner peers inside the human body by sweeping a person with a .3 millirem X-ray. By comparison, a standard medical exam exposes patients to 40 millirems, and a typical person receives about 300 millirems of annual background radiation.

The Department of Energy is also working on a new scanner, but it can't comment on its capabilities in the wake of Sept. 11, said Staci A. Maloof, spokeswoman for the department's Pacific Northwest National Laboratory.

"I would say, you could smuggle about three pounds vaginally and a pound anally," McGeorge said.