It would have been difficult to spy on him too Crowley reckoned but for different reasons. He lived in London and which was always busy and where you only saw familiar faces if you traveled in the same areas at the same time each day. Additionally he had been on guard the whole time, watching and waiting for Hell to send it's minions up to collect him. He hadn't seen any spies.

"Maybe it's just a book or it contains that summoning spell which brought us all here. I can't believe I'm about to say this but..." Deep sigh, books were not really his thing, "We should get a look at it once we break out of here."