The spy provided intelligence involving an active ISIS plot to bring down a passenger jet en route to the United States, with a bomb hidden in a laptop that U.S. officials believe can get through airport screening machines undetected. The information was reliable enough that the U.S. is considering a ban on laptops on all flights from Europe to the United States.

The sensitive intelligence was shared with the United States, officials say, on the condition that the source remain confidential.

“The real risk is not just this source,” said Matt Olsen, the former Director of the National Counterterrorism Center and an ABC News contributor, “but future sources of information about plots against us.”