From The Grey House, Book Three, Protector of the Grey House:
Natalia sagged against him, believing his words. He was known to lie to his people, but she didn’t see any indication in his eyes. She pulled away though, still upset with the events of the past three days. She looked Vincent in the eye and started her tale.
“I found a group of Slayers four months ago who seemed to know a great deal about the Slayers in the Bay Area. They’d been around and for some reason or other decided to catalogue the Slayers. Helped them in deciding who was best for what job or some nonsense. There was a core group of four Slayers, all of whom lived in the city and shared an apartment. It took me three months of meetings for them to trust me.”