Graeme met his Beta in the dungeon.
Sam called him there so he could verify if his own nose was correct or if he was overthinking this. He had followed Andreas' scent down here, but then the scent trail vanished.
"Is it because he came down here looking for Zoe and then he went back up through the pack house? Or was this more recent?" Sam asked the question aloud that he had been pondering silently.
If Andreas knew how to hide his scent, then the faint scent that would be left behind like that which Sam had identified on Marius at the treehouse would have already dispersed. It wasn't an identifier scent in terms of helping pinpoint who exactly it belonged to, and it didn't hang around long. Both of those characteristics made it unlikely that any lycan would typically pick up on it at all, which was why Marius had been so surprised that Sam had caught on to it.