Hezbollah noticed that a series of prepaid cellphones used by the informants were only used rarely and only in very specific locations. They used this, along with the fact that the CIA always used the same codeword, PIZZA, to uncover and arrest the informants.
Underscoring just how bad an idea using the term “PIZZA” was, the informants were said to have always met at the same pizzeria. Reportedly it was a Pizza Hut in Beirut. The CIA has denied that it was actually a Pizza Hut, but declined to provide an alternative location.