Terror's Latest Trigger: Cellphones
Bombs Can Be Detonated
From Virtually Anywhere
In Wireless Modern World


Using cellphones to detonate explosives, as apparently happened in the Madrid bombings, is a phenomenon that is nearly impossible to stop from a technical standpoint, say telecom-industry and explosives experts.
Terrorists in last week's attacks in Spain apparently hooked up bombs to cellphones, which theoretically could have allowed them to detonate the explosives from the other side of the world. Hooking up a phone to a bomb also provides the option of using an alarm clock in the phone to detonate the explosive, which is how it appears one unexploded device was set up.
How it works: A wire within a phone is connected to the detonator in a bomb. When a call is placed to the phone, an electrical circuit is completed, providing power to the detonator and setting off the explosive.

"You set up your explosive device in Berlin, or wherever. Now, you decide you don't want to be anywhere near that thing when it explodes, so you fly over to San Francisco and dial the number of the cellphone," said Greg Baur, former international director of the International Association of Bomb Technicians and Investigators. "That bomb goes off, and you're halfway around the world."
The use of cellphones to detonate a terrorist bomb isn't new. The Irish Republican Army attempted this unsuccessfully, according to Magnus Ranstorp, a terrorism expert at St. Andrews University in Scotland. There also is growing evidence that cellphones were used in last year's May 12 bombings in Saudi Arabia that killed 35 people.
But short of shutting down a country's cellphone network, there isn't much that can be done to reduce this risk. Indeed, the proliferation of radio devices -- in everything from cellphones to garage openers to hand-held devices that remotely unlock car doors -- means much of the modern world is virtually blanketed with wireless radio-wave technology.
Security services around the world try to minimize the risk of radio-controlled bombs. Pakistani President Pervez Musharraf's motorcade is equipped with radio-jamming devices. Those devices apparently helped to delay the explosion of bombs that had been set up under a bridge and were intended to assassinate him in December. The system in his car effectively blocked the receivers attached to the bombs.
U.S. investigators generally are cautioned not to use cellphones near suspected bombs on the chance that radio waves might trigger them. In Northern Ireland, bomb squads called to the site of suspected explosives also bring jamming equipment, according to Mr. Baur.
Cellphones can allow a large operation to be run by just a few people, since the bombers aren't being blown up along with their bombs. "All the bombs went off within four minutes, so it would have been possible to detonate the blasts from just one or two phones," Dr. Ranstorp said in a telephone interview about the Madrid bombings.
Authorities investigating the bombings in Saudi Arabia "seized cellphones which appeared to have been modified to trigger improvised explosive devices," according to a U.S. Federal Bureau of Investigation bulletin released to American law-enforcement authorities last June.
"During the past decade various international terrorist groups have used cellular telephones as well as pagers and commercial radio systems as a remote control method to trigger IEDs -- improvised explosive devices," according to the bulletin. "The FBI possesses no information indicating these devices have been or are being used in terrorist operations in the United States. However, law-enforcement agencies should remain alert to the potential use of such devices and incorporate awareness into their counterterrorism preventative measures."
The soaring use of cellphones that can't be traced back to their owners contributes to the problem, experts say. Getting an untraceable cellphone to use in this manner is fairly easy, particularly outside the U.S., where most cellular users subscribe using prepaid systems that don't require identification or signing a contract. In the U.S., almost 90% of users have contracts that require extensive application processes, including a credit check.
Vodafone Group PLC, the world's biggest cellular operator in terms of revenue, says 55% of its users around the world don't have contracts. The figures range as high as 82% in Egypt and 92% in Italy. Company spokesman Tim Brown said he doesn't expect that to change.