The mail bomb discovered by intelligence agents in Dubai and England were designed to blow up in flight en route to the United States, officials say. Despite being addressed to fictitious people at two Chicago synagogues, the timers were set to trigger while the cargo plane taking them overseas was in the air.

“We’re looking at the potential that they would have been detonated en route to those synagogues aboard the aircraft as well as at the destinations,” Brennan said in an interview on CBS’ “Face the Nation.” “But at this point, I think, we would agree with the British that they were designed to be detonated in flight.”

He was referring to statements by senior British officials Saturday that one of the devices, intercepted at the East Midlands airport in central England, could have been triggered to go off while in the air and that it was powerful enough to bring down an airliner.

Authorities also have a name of who they believe to be the designer of the bombs, a member of Al Qaeda of the Arabian Peninsula named Ibrahim Hassan Asiri, who allegedly also built the failed Christmas Day underpants bomb. This bomb, stuffed in a printer cartridge with wires sticking out, was similarly unsubtle, but according to officials more sophisticated.

The persistence of the Yemeni offshoot of Al Qaeda, which has orchestrated the last several failed attempts at terrorism against the United States, is likely to lead to more covert operations in the country. But it’s important to point out that the intelligence source that stopped this effort came from Saudi Arabia. In other words, maintaining alliances works a lot better than hunting down every last member of Al Qaeda. There are thought to be only 300 Al Qaeda in Yemen, and it simply doesn’t take many people to attempt a plot like this, which basically mirrors the Unabomber attack. It’s a sign of their weakness rather than their strength. And the best way to disrupt it is through police work, human intelligence.