Expert: Terrorists look to hide bombs in common items

“The smart bad guys will look at what you’re doing and find a weak point,” said Billy Green, a bomb expert for a private security consulting firm in Raleigh.

Green said terrorists want to make a “splash,” and the newest twist on terrorism is hiding explosive material in a common item.

“You've got to have the time, and you've got to have the operator trained to the degree to look at an X-ray and determine that it's unusual,” he said.

Green said the idea of using a printer cartridge is to hide the components in something that, if X-rayed or examined visually by an untrained person, wouldn’t necessarily arouse suspicion until the device had a chance to initiate.

Green said mail bombs can be on a timer or can be triggered by the opening of the package or by a remote device like a cell phone.

Unfortunately, he said, neither shipping companies nor airlines have the time or money to screen every package.

“If you've got a thousand packages an hour going through some screening port or something like that, there's no way in the world to screen those things effectively,” Green said.

While it’s unclear whether the sender ever intended last week's mail bombs to get to Chicago, Green said, it is ultimately up to public and private entities to screen their own mail in order to keep their employees safe.

“It has to be the end-user protecting themselves because that's where the responsibility is,” he said.