Notes from a Hatter Spy is a written note found in The Brigmore Witches.
Transcript
There has been interesting activity since our raid on the Dead Eels a few days ago. It looks like Wakefield has been rooting out Lizzy loyalists and chasing them off or making an example out of them with some gruesome killing. I don't think he's got much of a hold on this gang, and things are likely to fly apart before long.
Also, I swear I saw a woman lurking on some rooftops last night, spying on the Eels. She saw me looking at her and just... disappeared. Perhaps you'll know what to make of that.
- Oscar
Location
It can be found in an abandoned second floor apartment near the entrance to the Drapers Ward Riverfront.