This Washington Post story talks about how al Qaeda mayhem mentors tell wanna-be jihadists to go the low-tech route in planning terror attacks.
Counterterrorism officials have warned for years that Osama bin Laden and his lieutenants have tried to obtain weapons of mass destruction, such as a nuclear device or chemical or biological weapons. In response, U.S. military and intelligence agencies have invested vast amounts of money to block their acquisition.
So far, however, al-Qaeda and its affiliates have relied almost solely on simple, homemade bombs crafted from everyday ingredients -- such as nail-polish remover and fertilizer -- when plotting attacks in Europe and the United States.
The makeshift bombs lack the destructive potential of the conventional explosives that rake Iraq on a daily basis. They are also less reliable, as demonstrated by the car bombs that failed to go off in London last week after the culprits tried to ignite them with detonators wired to cellphones.
But other attempts have generated plenty of mayhem and damage, including the kitchen-built backpack bombs that killed 52 people in the London public transit system on July 7, 2005.
"It makes no difference to your average person if somebody puts a car bomb out there that is crude or one that is sophisticated," said Chris Driver-Williams, a retired British major and military intelligence officer who studies explosive devices used by terrorist groups. "If it detonates, all of a sudden you've got a very serious device and one that has achieved exactly what the terrorists wanted."